Let no one despise the ridges on account of their smallness, for they are in some
respects the
most important of all anthropological data. We shall see that they form patterns
considerable
in size and curious variety in shape, which are little worlds in themselves.
-Sir Francis Galton
PERSONAL IDENTIFICATION
Personal Identification
- These are peculiarity/characteristics/trait by which an individual is
identified or that which make a person unique
Identify general characteristic down to specific characteristics
*General Characteristics – color, brand name
*Specific Characteristics – any imperfection or indication for a particular object
or person at that will be the sole bases of identifying individual characteristics.
Examples of indications or imperfections are missing wheel on a trolley,
scratches, tattoo, and scar etc.
Process of Identification
 Naming Somebody
- An act of recognizing and naming somebody or something
Examples: we can identify them with familiarity of the person
 Proof of Identity
- To prove that somebody is who he or she claims to be
Example: use of identification card, enrolment form.
Importance of Personal Identification
- Determination of the individuality of a person or a thing
 History
- During the ancient period, personal identification is very important since
recidivist or repeat offender is given severe penalty of found to be one.
To avoid committing mistake in identifying a person, we need to establish
a systematic method of establishing the identity of the person thus we
have this so called fingerprint identification as a means of personal
identification.
Some Important Details in Science that there certain characteristics of a man
and a woman that will never change.
 Biological Traits that will never change
- Fingerprint and DNA
Although fingerprints, or grafted from other skin of the body can be
altered by surgery but never on DNA.
John Herbert Dillinger – he poured an acid onto his skin causing his
fingerprint disappear temporarily. What he did not realize however is that
even though we remove the epidermis of our skin or the skin showing our
fingerprint, in due time it will reappear again or be back again.
Roscoe Pitts – While he is in prison, he learned from one of the prisoner that
you can replace your fingerprint from grafted skin of the other parts of the
body. What he did then was to look for a doctor to operate on him from
removing his friction skin and grafted from a skin on his buttocks. “The man
without a fingerprint”
Importance
- In the prosecution of the criminal offense, the identity of the offender and
the victim must be established, otherwise it will be a ground for the
dismissal of the charge or acquittal of the accused.
o The identity of the victim and offender is both important in the
investigation of the criminal offense. In most cases, they found
bodies and unfortunately, there is no identification
o In the investigation of Homicide cases of an unknown cadaver, the
victim should be first identified because it is impossible for
investigators to find a lead or to pinpoint a suspect if they look for
the identity of the perpetrator first. We try to identify the cadaver
inorder to come up with a deduction who could have been
responsible of the death of that person. Modus Operandi too.
- Identification resolves the anxiety of relatives of missing people
o Person is considered missing after more than 24 hours. In cases of
abduction, it requires automatic response of Police Department.
Months and weeks passed, there is still a chance and Years passed
lesser chance of finding missing person.
o If relative is missing for a longtime, try searching at morgues.
o Anything that is out of the ordinary need explanations
- Identification may be needed in some transactions
o Bank Transactions (on signatures)
Methods of Identification
1. Ordinary Method
- Those which laymen used to prove identity where training, or special skill or any
instrument or procedure is not required for the identifier.
o Not requires education and only needs brain and 5 senses.
Anybody can do this and can become ordinary witness. What they
usually ask to ordinary witness is that “Have you heard it” “Did you
see it?” or any questions that involves their 5 senses. If none of them
appears to be experienced firsthand, it means that there is no
observation. Requirement for Ordinary Witness, You need to have
the ability to perceive and make your perception known to others
without addition or division.
o Hearsay evidence cannot be used as per stated in the rules of court
and because of the possibility of there will be addition or division to
it except for dying declaration. Dying declaration is hearsay by
nature but the law still accepts. Requirements of Dying declaration,
the person is under impending death and the declarant is aware of
it. Police officer in a scene with the declarant should ask whether
the declarant is dying to satisfy the requirement of the law but as an
officer, you also need to assess the extent of the injury. 1st question
to be asked is “who did this to you?” and whatever information is
given to you, you have to record it to use as a testament for dying
declaration.
Ordinary Method may Include:
a. Branding – done to cows, carabao (they use hot metals and imprint on the
skin)
b. Mutilation – cut fingers, ear piercing
c. Tattooing – body is already decomposing the tattoo is still there
d. Photographic Method – commonly used
e. Descriptive Clothing – commonly used (last seen wearing…)
f. Observation and Description (gait, scar, color of hair, height, physical
disabilities, etc…)
2. Scientific Method
- Those based on scientific knowledge used by trained men which is usually
based on exclusion and comparison.
o Main method employed in scientific method is Exclusion and
Comparison in a way that you cannot apply forensic science
methodologies of you do not have anything to compare a
specimen. Compare them to files and the suspect, if no files and
suspect, the forensic evidence is useless.
o Automated Fingerprint Identification System (AFIS) – a database of
fingerprints from known criminals. The database will look for 10
nearest match and the fingerprint technician will do the
comparison. It still need human intervention to avoid error. Ex: If a
fingerprint we found in a crime scene is not found on AFIS nothing
will change because we need to compare that fingerprint to
something. If ever we have a suspect and the suspect’s fingerprint is
found in the crime scene it doesn’t mean already that the suspect is
guilty. You are only there to determine whether two specimen is
similar. The function to determine the guilt of the person is not within
the scope of being a forensic scientist but it is on the hands of the
judge or the court.
Scientific Method may include:
a. Anthropometry
b. Dactyloscopy
c. Orthodontology – Root of Teeth are different
d. DNA Analysis – Biological evidence can be subject for
Exclusion and Comparison
DNA Analysis but the problem is if they are twins
e. Voice Comparison – first cry, 1st time vocal cords are already
being developed. Grown up, we have the ability to mimic the
voice of other people but the frequency as well as the pitch of
the voice can never be replicated from one person to another,
We need however specific machine to tell us not our own hearing
f. Handwriting Analysis
h. Blood Typing – Preliminary testing for DNA Analysis. You cannot
compare a blood type O to Blood type A.
i. Iris Scanning
Anthropometry/Anthropological Measurements
- A method of criminal identification introduced by Alphonse Bertillon, a
French Anthropologist. Used 1st scientific method of identification and as a
result Bertillon became the Father of Personal Identification.
- Bertillon believed that certain body parts especially the bone is
unchangeable at the age of 20 years old.
- Aside from body measurements, Bertillon also make use of portrait parle at
the same time getting the fingerprint
- Bones do not change in dimensions after adulthood, and therefore by
taking measurement of another bone, the identity of an individual can be
established.
- The practice is very time consuming because body parts such are
measured like the spatting or standing height, length of the arms, sitting
height, measurement of the left ear, circumference of the head, size of
the foot, elbow.
Bertillon’ System relied on:
Portrait Parle – detailed description of the individual
Full length and profile photographs – until now being used (now known as mug
shot)
These measurements are recorded on cards and classified according to the
length of the head. The supremacy of Bertillon system infiltrates worldwide and
was accepted for almost 30 years. Bertillon system became unusable because it
is found out to be inferior and proven to make a lot of mistakes or prone to errors
using this method.
In 1903, a prisoner by the name Will West was sentenced to incarceration at the
United States Penitentiary at Leavenworth, Kansas.
During his processing, the records clerk obtained Will West’s Bertillon
measurements and photograph
Will West denied ever being incarcerated at the facility
IDENTIFICATION METHODS AND THEIR CHANCES OF FAILURE
NOS
1
2
3
4
5
IDENTIFICATION METHOD
Measurement of Height (Quaetelet’s
Method)
Comparison of Pubic hair
Comparison of Scalp hair
Anthropometry (Bertillon’s Method)
Teeth Bite Marks
6
7
Dactylography (Fingerprints)
DNA Fingerprinting
CHANCES OF FAILURE
1 in 4
1 in 800
1 in 4500
1 in 268 million
1 in 2.5 bil. (Now 1 in 2
mil.)
1 in 64 bil.
1 in 2 x 10
They measure Medullary Index and Lanugo hair for children.
Best police force – Scotland Yard
The Jones Case
- 1904 - Scotland yard already implements Henry System. NY detective
Sergeant Joseph Faurot became the first American to be trained in the
Henry System of Classification
- Upon his return, he was told to forget about his training and was assigned
as a walking beat patrol officer. (The Chicago police: forget about your
training. And made him a patrol officer)
- 1906 – Sgt. Faurot arrested a man in formal wear without shoes. And was
captured because he went out of the window of the hotel
- Man claims to be James Jones
- Took Fingerprints was sent to Scotland yard and found out to be Daniel
Nolan
- He was sent to prison for seven years
The Scotland Yard through Edward Richard Henry was the first person to fully
develop or perfected the first systematic classification of fingerprint (it was
already existing because of Francis Galton developed first systematic
classification of fingerprint)
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Fingerprints, as well as palm prints and footprints, are made up of friction
ridges.
The Scientific Working Group on Friction Ridge Analysis, Study and
Technology (SWGFAST) defines a friction ridge as “a raised portion of the
epidermis on the palmar or plantar skin, consisting of one or more
connected ridge units.”
The word “palmar” refers to the hand: the palm of the hand, finger joints,
and fingertips.
The word “plantar” refers to the bottom of the foot and the toes.
Friction ridges are minute, raised areas of skin similar in contour to
mountain ranges. Just as mountains are pushed up through the earth’s
crust to the surface, so too are friction ridges pushed up through the layers
of the epidermis to the skin’s surface.
Though friction ridges all appear to be of the same width and height, they
are extremely variable. It is not easy to see these variations with the naked
eye.
Why do humans and primates have friction ridge skin on hands and feet?
It is FRICTION.
Friction is the measure of resistance when the surfaces of two objects are
pressed together, or when two objects move against each other.
An example is the friction of automobile tires. When the break is applied
with force, the rubber of the tires may leave skid marks on the road.
Another example of friction is the action of scraping a wooden surface
with sandpaper. The rougher the surface, the more friction is created
between two objects.
The friction ridges on the hands come into contact with objects
constantly. We use our hands to grip objects throughout our daily lives. We
turn doorknobs, drink from glasses, type on keyboards, drive vehicles, and
write with pens.
Our friction ridges allow us to perform all of these tasks. If we did not have
friction ridges on our fingers, we could not easily grip a smooth drinking
glass or a cell phone.
Friction ridges create a rough, textured surface that provides resistance
between our hands and anything we touch.
FINGERPRINTS AS FORENSIC EVIDENCE
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Fingerprint analysis is one of the most common and historically consistent
sub-disciplines of the forensic sciences. For over 100 years, fingerprints
have been used to identify individuals.
Fingerprints are taken from suspected criminals who have been arrested
and compared to prior arrest records.
Fingerprints are developed at crime scenes and in laboratories using
fingerprint powders and chemical processing methods. They have been
used to solve countless crimes over the course of history. Every day,
thousands of fingerprint examiners all over the world make fingerprint
identifications.
THERE ARE THREE MAJOR FACETS OF FORENSIC SCIENCE:
1. TO demonstrate whether or not a crime has been committed;
2. TO identify the individuals involved and how those individuals are
associated with other individuals and with the crime scene;
3. TO reconstruct the crime scene and the sequence of events that
occurred. Fingerprints may be used throughout these processes to
provide investigative leads.
The diagram below illustrates the evidence linkage triangle, a
common pictorial representation of the link between the crime scene,
victim, and suspect. There may be more than one suspect, victim, or
even crime scene. Fingerprints can link a victim to a crime scene, a
suspect to a crime scene, and/or a suspect to a victim.
The evidence linkage
triangle demonstrates
the link between the
crime scenes,
Victim, and suspect.
Fingerprints are collected from items of evidence to provide
investigative leads. But they are also evidence in themselves.
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There are two types of evidence:
TESTIMONIAL AND PHYSICAL.
Testimonial evidence refers to verbal accounts such as eyewitness
statements or transcripts of interviews. This type of evidence is subjective,
meaning it is subject to either intentional or unintentional biases of the
individual.
Physical evidence includes both physical evidentiary items (weapons,
bloody clothing, etc.) and forensic evidence such as fingerprints, trace
evidence, and DNA.
INTRODUCTION TO FORENSIC SCIENCE
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Friction ridge development may have arisen due to thousands of years of
evolutionary development, but it has another use in modern science,
specifically forensic science.
The word forensic comes from the Latin word FORENSIS, which means “of
the forum.”
In ancient Rome, the forum, or marketplace, was the centre of civic life.
Civil and criminal cases were heard in public before an assemblage at
the forum where each side would give an oration to explain their
complaint. The forum was essentially a court, though not in the sense we
would think of a courtroom today.
Forensic science is the intersection between science and legal
matters.
Today, forensic science refers to any science applied to legal matters.
There are many sub-disciplines of forensic science, but all apply the topic
to matters of law.
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For example, FORENSIC ANTHROPOLOGY is the study of decomposed or
skeletonized remains as it applies to matters of the law. FORENSIC
ENTOMOLOGY is the study of arthropods—insects and spiders—as they
apply to legal matters. “Legal matters” refer to crimes or prospective
crimes as well as civil disputes.
No matter what sub-discipline you intend to practice, legal matters are
decided in a court of law.
Courtroom testimony is a critical final step in the analysis of forensic
evidence, whether that evidence is bones, insects, or fingerprints.
During this process, the forensic scientist explains what was done during
the forensic investigation. Explaining the science behind the forensic
analysis to a jury is often the most challenging part of the testimonial
process.
The forensic scientist may also be asked to recount the history, theory,
and research, and investigative methods of their science.
FINGERPRINT ANALYSIS
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Fingerprint evidence is valuable because fingerprints are unique.
No two fingerprints are alike. Thus, fingerprint examiners can trace a
fingerprint back to its source.
Fingerprint comparison is the process of comparing two friction ridge
impressions to determine if they came from the same source (i.e., did the
same person make both impressions).
Fingerprint examiners compare unknown fingerprints from crime scenes or
items of evidence to known fingerprints and make a determination as to
the source of the prints.
THERE ARE TWO TYPES OF STRUCTURAL CHARACTERISTICS of fingerprints that
allow fingerprint examiners to compare fingerprints and make identifications:
PATTERN TYPES AND MINUTIAE.
1. Pattern types—arches, loops, and whorls—are not unique to the
individual. They are class characteristics.
- Class characteristics are those features that place an individual or object
in a group or subcategory.
2. Minutiae (pronounced mi-noo-sha) are individualizing characteristics.
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Individualizing characteristics are those features that are unique to one
particular person or thing.
Fingerprint examiners analyse both the class characteristics and
individualizing characteristics of fingerprints in order to reach a conclusion.
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Class and individual characteristics are used to describe many forensic
evidentiary items such as shoeprints, tire tracks, biological evidence, and
firearms evidence.
Examples of class and individual characteristics are observable
everywhere. For example, a vehicle may demonstrate both class and
individualizing characteristics.
The class characteristics include the following features: color, number of
doors, make and model and vehicle type (ie. Sedan or wagon etc).
But what if there are two vehicles which are exactly alike and you are
looking for a vehicle that have previously involved in a hit and run
incident? What individualizing characteristics can you use to distinguish
the vehicle involved in the incident?
FINGERPRINT PATTERN TYPES are class characteristics and are therefore
used to narrow down the potential field of candidates who may be the
source of the fingerprint in question, just like the color and make and
model of a vehicle narrow down the possibility that the vehicle is the
vehgicle of interest.
THERE ARE THREE CATEGORIES OF FINGERPRINT PATTERNS:
Arch, loop, and whorl
THERE ARE EIGHT SUB-PATTERN TYPES WITHIN THOSE CATEGORIES:
Ulnar loop, radial loop, plain whorl, double-loop whorl, central pocket
loop whorl, accidental, plain arch, and tented arch.
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Other class characteristics of fingerprints include the presence of creases
and scars, the ridge count of a loop, and the whorl tracing of a whorl
pattern.
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In order to reach a conclusion, the fingerprint examiner must also analyse
the minutiae: the individualizing characteristics in a fingerprint.
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The word “minutiae” refers to small details. The friction ridges that make
up a fingerprint pattern are not continuous, as they may appear at first
glance.
THERE ARE THREE POSSIBLE CONCLUSIONS TO A FINGERPRINT COMPARISON:
IDENTIFICATION, EXCLUSION, OR INCONCLUSIVE.
Do the fingerprints match? We call this a positive identification, or
individualization. This means the fingerprint originated from one source: one
individual and no one else.
Exclusion occurs when the same corresponding areas of two fingerprints are
incompatible. Inconclusive result is reached when a fingerprint can neither
be conclusively identified nor eliminated.
UNIQUENESS AND PERMANENCE
Two main premises form the basis for the science of fingerprint identification:
1. FINGERPRINTS ARE UNIQUE.
2. FINGERPRINTS ARE PERMANENT.
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Uniqueness means that there are likely no two people in the world with
the same fingerprints.
Even identical twins, with identical DNA, have different fingerprints.
We know fingerprints are unique because of the inherent randomness of
nature.
Throughout the history of fingerprint identification, it has been widely
accepted that no two people have the exact same fingerprints.
Permanence means your fingerprints do not change throughout your
lifetime. They form in utero from the deepest layer of the epidermis and do
not change as you age.
This text explores the uniqueness and permanence of fingerprints in many
contexts.
It will first address the background, theory, and history of the science of
fingerprint identification; followed by a discussion of the development,
visualization, and documentation of latent fingerprints from evidence and
crime scenes; and finally fingerprint comparisons and courtroom
testimony.
INTRODUCTION-2
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The first real method of identification was the artist’s rendering.
Drawing a picture of what was seen by another individual is not an easy
task.
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The challenge has always been to relay the information in such a way
that it is understandable to the person who is doing the sketch.
There have always been those individuals who have used their creativity
to generate a likeness of an individual.
As standardized terminology and descriptors were developed, the quality
of the sketch was remarkably improved.
Today we commonly refer to this method as a POLICE ARTIST SKETCH.
The problem that has always existed with an artist’s rendering is the ability
of the artist to put onto paper what one individual has put into words to
describe another individual.
An artist’s rendering is never going to produce or replicate an exact likeness of
an individual. That is why, even today, the police sketch is, at best, a very close
likeness of an individual.
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Coming in a close second, due to the lateness of its development, is the
photograph.
A photograph, as we know, will produce an exact likeness of an
individual.
The first such device for photography was the Daguerreotype which was
first used in Brussels around 1843.
A photograph was developed on a light-sensitive silver-coated metallic
plate.
Later a glass plate was used. This method, to say the least, was extremely
cumbersome, the photographs that were taken were not extremely high
quality, and the equipment associated with the task made it difficult at
best to take photographs in a less than the controlled environment.
As time has evolved, these techniques or processes were replaced with
cellulose acetate, commonly referred to as camera film. As with all
inventions or technology, photographic technology has become very
sophisticated, easy to use, and for the most part, inexpensive.
That is why the portable camera has made the job of photographic
documentation so much easier and desirable.
However, with film, there was still one major drawback. One could not
instantly see the photograph one was trying to capture. Newer
technology, such as Polaroid instant cameras, soon filled the void of
immediacy.
However, with the immediacy of the photograph, certain sacrifices had to
be made such as quality and longevity.
The photos taken with the Polaroid-type cameras could not capture the
quality depth of field and the photos were not long-lasting.
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As the technology evolved, so too have the types of cameras, to the
point that today we have good quality digital cameras that allow us to
immediately view that which we have just photographed.
If the photograph does not capture sufficient information, another
photograph can be immediately taken.
The quality and affordability of the digital camera is attainable by most
law enforcement and governmental agencies today.
It is also said that film, as we know it today, will be replaced with digital
photography due to cost, dependability, usability, and storage.
However, cameras are not always present during the commission of
crimes, although that is changing with the advent of the mini-cam or the
video/digital recorder, as well as the ubiquitous digital phone.
An ideal systematic method of identification combines the features of a
sketch, a photograph, and other methodology to document the specificity
of an individual, a location, or an event.
The first such documented system, which combined the photograph and
physical description, was a system developed by Alphonse Bertillon, circa 1883.
This system became known as Bertillonage or anthropometry.
THE SYSTEM CONSISTED OF FOUR PARTS
1.
2.
3.
4.
ANTHROPOMETRY (BODY MEASUREMENTS)
PORTRAIT PARLÉ (SPOKEN PICTURE OR VERBAL DESCRIPTION)
PHOTOGRAPHS
FINGERPRINTS
BERTILLONAGE
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Anthropometry consisted of taking specific body measurements metrically
and classifying those measurements into small, medium, and large.
That information was then recorded and placed on index cards and filed.
The body measurements consisted of the length of arms, sitting height,
caliper measurements of the head, right arm, left foot, left middle finger,
left forearm, and right ear.
When measuring women, measurements of the head, left foot, and elbow
were excluded.
For boys and young men, classification was according to the color of
eyes and details of ears.
BERTILLON'S PRINCIPLE OF ANTHROPOMETRY
1. The human skeleton is unchangeable after the twentieth year. (Thigh bones
grow but the spine curves to compensate.)
2. It is impossible to find two human bones exactly alike.
3. Necessary measurements could easily be taken with the aid of simple
instruments (calipers).
The other part of Bertillonage was known as PORTRAIT PARLÉ, which literally
means “spoken picture” or physical description.
THIS PART OF THE SYSTEM CONSISTED OF FOUR PARTS.
1. Determination of colour of the left eye, hair, beard, and skin.
2. Morphological determinators such as shape, direction, and size of every part
of the head.
3. General determinators such as grade of stoutness, carriage, voice, language,
dress, social standing, height, and weight.
4. Description of indelible marks such as birth marks, scars, and tattoos.
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Bertillon also required the use of a full face and profile photo which were
affixed to the cards.
And finally, Bertillon affixed fingerprints to the rear of the index cards;
however, Bertillon always championed his anthropometry as a means of
identification.
Oddly enough, it was fingerprints, which Bertillon recorded, that were
responsible for the ultimate demise of the anthropometrical system.
Shortcomings of the Bertillon system of identification were the cause of the
demise of the system in its totality.
Examination of the Bertillon system reveals the following shortcomings:
1. The system was limited to adults, as the theory espoused by Bertillon said the
skeleton remained unchanged after the twentieth year. What about those
persons under the age of twenty? Although provisions were made for children,
the provisions proved insignificant.
2. The system was often marked by significant differences in measurements of
the same criminal by different examiners. As with any repetitious task, often the
practitioner became complacent and was not as vigilant as one would desire.
3. Soft property of the ears resulted in that portion of anthropometry being
dropped.
4. The system was extremely slow (measuring devices consisted of calipers and
similar measuring devices, which in and of themselves were laborious to use).
5. The West Case of Ft. Leavenworth, Kansas, 1903. Will West was sentenced to
prison, and when being processed was accused of being William West on the
basis of his physical appearance and anthropometrical measurements. William
West was called from the prison population where he was serving a life
sentence for murder. The appearance of the two men was striking and their
physical attributes were identical. Fingerprints were then taken in an attempt to
determine identity. When compared, the prints did not match. Were they two
twins who had never met? The two Wests were African American and it has
been speculated that they may have been the offspring of slaves, separated at
birth, and had never met until this fateful day.
Although there were shortcomings to the Bertillon system, there were values
established that are still in use today.
The values established by Bertillonage were:
1. Establishment of a full face/profile fixed-scale photograph. (Today the
addition of numbers on the photographs serve as an additional identification
marker.)
2. Establishment of the use of a detailed description (portrait parlé/physical
description). (General descriptors such as height, weight, race, age, and
specific descriptors such as scars, marks, and tattoos are used.)
3. Establishment of the concept of repeated subdivision of data for ease of filing
and searching (gathering information and categorizing it in a systematic form).
4. Demonstration that fingerprints could be used to individualize identity.
Although Bertillon promoted the idea of a systematic method of identification,
the shortcomings of his system gave rise to what would become the most widely
used method of identification and individualization worldwide for the next
eighty years: FINGERPRINTS. Technology did not come to the forefront for
purposes of individualization through bodily fluids until the 1980s with the advent
of the use of deoxyribonucleic acid (DNA).
FINGERPRINTS
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The use of fingerprints began in earnest as a method of identification in
the late 1800s and early 1900s with the establishment of fingerprint
classification systems.
To thoroughly understand fingerprint identification and the methodology
associated with the process, it is necessary to understand the terminology
associated with fingerprints that have been established.
DEFINITIONS ASSOCIATED WITH FINGERPRINTS
Dactylography, a Greek term that translates as “finger writing.”
Dactyloscopy, a Greek term that translates as “to view the fingers.”
Dermatoglyphics, a Latin term that translates as “skin carving.”
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How, one might ask, do these terms apply to fingerprints? The terms are all
associated with the fingers in one way or another and demonstrate that
the pursuit of knowledge of fingerprints has been around for centuries.
The modern day equivalent or usage of these terms can be converted
into the scientific study of fingerprints for the purpose of identification.
FINGERPRINT— the impression or reproduction left on any material by the friction
skin of the fingers. Most often we see the impression left by the fingertips or the
bulb of the fingers. But the friction skin covers the entire area of the inner hand
(the palm) and fingers.
PALM PRINT— the impression or reproduction left on any material by the friction
skin of the palms.
Footprint/toe print— the impression or reproduction left on any material by the
friction skin of the foot (feet) or toe (s)
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It should be noted that friction skin is found on the hands and the feet of
individuals.
The friction skin is the outer layer of skin that contains many of the
elements and characteristics we use to identify and individualize a print.
FRICTION SKIN— the skin on the inner hands and fingers, and on the bottom of
the feet and toes, which is characterized by alternating strips of raised ridges
and furrows arranged in a variety of patterns.
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The friction skin is found on both humans and anthropoids. In lower
mammals, friction ridge patterns are sometimes similar to ours. Friction
surfaces are sometimes padded in apes.
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The purpose of the friction skin, as the name implies, is to provide
resistance so that those surfaces containing friction skin will be able to
grasp objects. The friction skin forms during the third or fourth month of
fetal growth (approximately 120 days).
The process by which friction skin develops is through the formation of
small islands surrounding pores, which then develop to form ridges.
FRICTION RIDGE— the raised portion of the skin that leaves the impression or
reproduction.
FURROW— that portion of the skin lower and between the ridges.
A cross-section of the friction skin illustrates the various parts and layers of the
skin.
1. Epidermal layer: outer layer
a. Stratum corneum: surface skin
i. Friction ridges, furrows, and pores
ii. 1 to 2 mm thick
b. Stratum mucosum (Malpighi—inner skin)
i. Programs/forms outer skin
2 Dermal layer: (inner layer/2nd layer)
a. Dermal papillae
i. Determines ridge structure
b. Sweat glands and ducts
c. Nerves of touch (sensors)
d. Fat
Friction skin is permanent.
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That is, the skin does not change under normal conditions from the time of
formation until decomposition after death.
The exception is that, like other parts of the anatomy, the fingerprints or
friction skin will get larger as the body grows.
The specific characteristics will remain the same, however.
Friction skin will deteriorate with age as well as all skin, but classification
and identification normally will not be affected.
There is an adage that is often used to describe the permanence: under
normal wear and tear, the friction skin will remain unchanged throughout
one’s life.
Friction skin destruction (temporary or permanent) encompasses:
-
An injury penetrating into the dermal layer (second layer of skin), through
the dermal papillae, will result in the ridges not being regenerated.
Scar tissue will form to the extent that the damage occurred, and only
those ridges in the path of the injury should be permanently affected.
Injuries to the epidermal layer (first or outer layer) will repair themselves as they
were prior to the injury, for example, paper cuts.
-
-
There are many instances in legend where allegedly people have
sanded, burned, or surgically altered their fingerprints with permanent
results. Research has demonstrated what effect different techniques have
on the appearance of fingerprints.
Self-induced injuries cannot remove all ridges or the hands would be too
severely injured to be used. What one must understand is that friction
ridges cover the entire surface of the inner hands and bottom of the feet.
If the pattern area alone were disfigured, classification might be affected, but
identification or individualization would not.
In all likelihood, the pattern would be made more unique which would make
identification and individualization that much easier.
Other alterations to the friction skin whether it be surgical, occupational, or
medical can have an impact on the appearance. Examples are:
-
-
Skin grafts would result in either the old pattern being regenerated as the
graft skin wore away or the graft area remaining smooth. A new pattern
would not occur.
Occupational wear might wear down the ridges, but the cessation of the
work will result in the ridges becoming distinct again.
Disease can have an effect on the fingerprints as well;
-
-
Such as in the latter stages of leprosy, the skin may flake off and the
pattern may be lost.
Allergic reactions may have an effect on the ridges in that a temporary
change may occur but when the reaction disappears, ridges should
return to their configuration.
Other conditions such as warts, creases, or calluses may be present but
seldom affect classification and rarely, if ever, affect identification.
Based on the foundation and fundamentals of the aforementioned information,
a basis of the science of fingerprints was established:
1. Every finger contains ridge detail which is unique to that finger and no other.
2. Unique ridge details do not change (except in size) from approximately 120
days (3-4 months) after conception until decomposition after death.
3. A set of fingerprints lends itself to classification and therefore can be filed and
searched. Whether the system be manual or automated does not matter.
FINGERPRINT CLASSIFICATION— the process of assigning a formula, consisting of
numbers and letters, to a set of fingerprints determined by the pattern
interpretation and ridge detail of the fingerprints themselves.
FINGERPRINT IDENTIFICATION (INDIVIDUALIZATION)— the process of determining
that the same finger made two or more impressions based on the friction ridge
details of both impressions (to the exclusion of all others).
BASIC PRINCIPLES OF FINGERPRINT SCIENCE
BASIC PRINCIPLES OF FINGERPRINT SCIENCE (3 DOGMATIC PRINCIPLES)
PRINCIPLE OF INDIVIDUALITY
-
This principle states that the complex of the ridge details in a single
fingerprints or even part of one is not duplicated in any other finger. The
patterns may look similar but if a close scrutiny is made, their specific ridge
details are very different from one another. This was spoken by Galton
when he mentioned about the Minutiae of fingerprints or the Galton’s
Details.
PRINCIPLE OF PERMANENCY (A.K. A. Perreniality/Persistency/Constancy)
-
This states that fingerprints do not change in its ridge characteristics of FP
pattern throughout or life time of an individual and they persist after DEATH
until the skin is decomposed. Ridge characteristics are formed prior to
birth and remain constant through life except for growth and deep
scarification. Skin condition such as warts and blisters are temporary
impairments caused by certain occupations, e.g. bricklayers, carpenters,
have no permanent effect and the individual characteristics revert to
their natural alignment once the temporary skin condition has been
corrected.
INFALLIBILITY
-
This states that fingerprint is absolute and cannot be forged. It means that
when a person is identified by means of fingerprints, it is positive and
conclusive. The person may not deny that the fingerprints are not his own.
However, as experiences dictate, many FP experts are attacked on their
credibility and the accurateness of the processes he had made in order
to arrive to such conclusion. Lawyers would not question the principle but
rather on the expertise of the technician. Many of them would find
loophole on the procedures done not on the accurate principle.
HISTORICALBACKGROUND OF FINGERPRINTS
IMPORTANT RECORDS /EVENTS ON F.P.
Nova Scotia – prehistoric picture writing of a hand with ridge patterns was
discovered
Ancient Babylon – FP were used in clay tablets for business transactions.
Ancient China – thumb prints were found on clay seals. . Some of these seals
can be seen in the SMITHSONIAN INSTITUTION, WASHINGTON, D.C.. (TANG
DYNASTY, 618-907)
EMPEROR Te’ in Shi (BC 246-210) – the first Chinese ruler who devised a seal
carved from a white jade. Fingerprints during this time were used in business
transaction as a sign of acknowledgement of purchase.
To the Chinese, fingerprints are known as Hua Chi. Slices of matches of
fingerprints are kept to preserve the identity of people.
The arches are known as Lo (snail) and Loops as Ki (sieve/basket). The loops
are called upon as presage of good luck.
Persia, 14th century, various official gov’t papers had FP (impressions) and
one gov’t official, a doctor, observed that no two FP were exactly alike.
EARLY PUBLICATIONS CONCERNING FINGERPRINTS
1686, Marcello Malpighi, (GRANDFATHER OF DACTYLOSCOPY)
-
A professor of anatomy at the University of Bologna, noted in his treaties;
ridges, spirals and loops in fingerprints. He made no mention of their value
as a tool for individual identification.
1823, John Evangelist Purkinji, (FATHER OF DACTYLOSCOPY)
-
A professor of anatomy at the University of Breslau, published his thesis
discussing 9 FP patterns but he too made no mention of the value of FP for
personal identification.
THE 9 PATTERNS ARE NAMED:
1.
2.
3.
4.
5.
6.
7.
Transverse curves (plain arch)
Central Longitudinal stria (tented arch)
Oblique stripe (ulnar or radial loop)
Oblique loop (ulnar or radial loop)
Almond (whorl)
Spiral (whorl)
Ellipse-elliptical whorl (whorl)
8. Circle-circular whorl (whorl)
9. Double whorl (Twin loop)
1858, William Herschel - an English civil servant (India), required natives to
sign contracts with an imprint of their right hand – Hindu custom?
In 1880, Scottish physician, Henry Fauld - wrote that skin ridge patterns could
be important in identification work. A thief left his fingerprint on a
whitewashed wall – compared with 1st suspect - No match; compared with
2nd suspect with positive association. He recommended the use of thin film
of printers ink as a transfer medium and is generally used today.
During 1880’s, Sir Francis Galton - a British anthropologist and a cousin of
Charles Darwin, began his observations of FP as a means of identification.
-
-
In 1892, he published his book, “FINGERPRINTS”, establishing the
individuality and permanency of FP. The book included the first
classification system of FP.
Proposed three pattern types: loops, whorls and arches.
Galton identified the characteristics by which FP can be identified. The
same characteristics (minutiae) are basically still in use today and are
often referred to as the Galton’s detail.
FRANCIS GALTON mentioned that No two prints are identical. An individual’s
prints remain unchanged from one year to the next.
1788 – J.C.A. MAYER - He found that the fingerprints of two persons are never
alike. The ridges have similarities but never duplicated. (Principle of
Individuality)
1856 – HERMAN WELCKER took the prints of his own palm in 1897 (forty one
years later) he printed the same palm to prove that the prints do not change.
(Principle of Permanency)
1891, Juan Vucitech, an Argentine Police Official, began the first FP files
based on Galton pattern types. 1892, he made the first criminal fingerprint
identification.
-
-
He was able to identify a woman by the name of Francisca Rojas, who
murdered her two sons, and cut her own throat in an attempt to place
blame on other.
Her bloody print was left on a door post, proving her identity as the
murderer.
SIR EDWARD HENRY, an Englishman who, In 1897, proposed another
classification system which is still in use today. Most English-speaking countries
use some version of Henry’s classification system. The system was so
applicable that Henry emerged as the “FATHER OF MODERN FINGERPRINT
SCIENCE”, at least, as the first man who successfully applies fingerprints for
identification.
1882, Gilbert Thompson of the U.S. Geological Survey in New Mexico, used his
own FP on a document to prevent forgery. This is the first known use of FP in
the U.S.
FP IN THE UNITED STATES
1901 – First systematic use of fingerprints adopted by the New York Civil
Service Commission (Dr. Henry DeForrest-1902)
1903 – New York State Prison system began the first systematic use of FP in U.S.
for Criminals. Captain James Park of that institution installed the identification
system where the fingerprints of prisoners were taken and classified and the
fingerprint system was officially adopted in June of that year.
1904 – American police received training in fingerprint techniques from
Scotland Yard’s representatives
FINGERPRINT IN THE PHILIPPINES
GARRY JONES was the first one to teach fingerprints in the Philippines in the
Philippine Constabulary sometime in the year 1900.
The Bureau of Prison records show that of the year 1918 CARPETAS
(commitment and conviction records) already bear fingerprints.
The first Filipino fingerprint technician employed by the Philippine
Constabulary was Generoso Reyes, Capt. Thomas Dugan of New York City
Police Department and Mr. Flaviano C. Guerrero of the Federal Bureau of
Investigation, Washington, D.C. gave the first examinations in fingerprints in
1937. The first Filipina Fingerprint Technician was Isabela Bernales.
On December 23, 1933, the first conviction based on fingerprints was handed
by the Supreme Court of the Philippines in the case of People of the
Philippines versus Medina and was considered the leading judicial decision in
the Philippine Jurisprudence concerning the science of fingerprinting.
LEGALITY OF FINGERPRINTS
-
It is a universal knowledge that fingerprint is the most positive means of
personal identification.
As such, fingerprint as evidence is accepted in every court of justice in
any part of the globe.
Pioneers in the science of fingerprints like Galton and Locard believe in
the (although very remote like in 1 in 64 billion or 1 in 3 trillion) law of
probability in the duplication of fingerprints in two individuals.
The following are decided cases regarding fingerprint used as evidence.
In 1911, an Illinois court, in the case of People vs. Jennings [252 III. 534, 96 NE
1077 (1911)] pass upon the admissibility of fingerprint evidence.
-
In that case, fingerprint evidence was admitted as a means of personal
identification.
It was also held that persons experienced in the matter of fingerprint
identification may give their opinions as to whether the fingerprints found
at the scene of the crime correspond with those of the accused.
New Jersey, State v. Cerciello, in which fingerprint evidence was permitted to
be introduced.
-
-
-
In the Cerciello case, the defendant argued that it was an error to allow
the testimony of the experts explaining the comparison of fingerprints
obtained from the defendant voluntarily with those fingerprints found
upon a hatchet near the body of the deceased when the body was
discovered.
The New Jersey Court of Errors and Appeals held, “in principle, its
admission as legal evidence is based upon the theory that the evolution in
the practical affairs of life, whereby the progressive and scientific
tenderness of the age are manifested in every other department of human
endeavor, cannot be ignored in legal procedure.
But that the law in its effort to enforce justice by demonstrating a fact in
issue, will allow evidence of these scientific processes which are the work
of educated and skillful men in their various departments, and apply them
into the demonstrations of fact, leaving the weight of the effect to be
given to the effort and its results entirely to the consideration of the jury”,
[State v. Cerciello, 86 NJL 309, 90 Atl. (1914)].
In the case of State v. Conners [87 N.T.L. 419, 94 Atl. 812 (1915)]
-
It was held competent to show by a photograph the fingerprints upon
the balcony post of the house entered, without producing that post in
court, and to show by expert testimony that the fingerprints found on the
post were similar to the fingerprints of the defendant.
In the case of Lamble v. State [Lamble v. State, 96 N.T.L. 231; 114 Atl. (N.J) 346
(1991)]
-
Which involved the discovery of fingerprints on the door of an automobile,
the court was of the opinion that it was not necessary to produce the
door, it should be sufficient along with the identification of the fingerprints
by an expert to show these of the defendant. The court referred to the
previous decided case of State v. Conners.
In the case of Commonwealth v. Albright, [101 Pa. Sup. C.L. 317 (1931)]
-
-
a fingerprint expert testified that the fingerprint on a piece of glass,
establish to be from a pane in a door that had been broken to effect
entrance to the house was the same as the impression of the defendant’s
left index finger and he explained in detail the points of identity which led
him to that judgment.
In the Albright case, the court stated, “it is well settled that the papillary
lines and marks on the fingers of every man, woman and child possess an
individual character different from of any other person and that the
chances that the fingerprints of two different persons maybe identical are
infinitesimally remote.
In a California case, People v. Corral [224 cal. 2d 300 (1964)],
-
The court stated, “It is completely settled law that fingerprints are the
strongest evidence of the identity of the person”.
The Doctrine was reasserted in another California case, People v. Riser [47
cal. 2d 566 (1956)]
-
In which the court stated, “Fingerprint evidence is the strongest evidence
of identity and is ordinarily sufficient alone to identify the defendant”.
The US Supreme Court in the case of Schmerber v. California [Schmerber v.
California, 384 US, 757, 763, 764 (1966)],
-
-
Held that the introduction into evidence of fingerprint impression taken
without consent of the defendant was not an infringement of the
constitutional privilege against self-incrimination.
The high court held that it is constitutional to obtain real or physical
evidence even if the suspect is compelled to give blood in a hospital
environment, submit to fingerprinting, photographing or measurement,
-
write of speak for identification, appears in court, stand or walk, assume a
stance or make a particular gesture, put on a cloth that fits him, or exhibit
his body as evidence when it is material.
The Schmerber case points out the fact that the privilege against selfincrimination is related primarily to “TESTIMONIAL COMPULSION’’.
In the Philippines, several decided cases could be cited where fingerprints
evidence was admitted, considered and appreciated by the appellate courts
with even lesser number of ridge similarities.
In the BILANGWA V. AMADOR case, (Court of Appeals No. 37320-b),
-
a fingerprint expert and constabulary sergeant testified and successfully
defended fingerprint evidence based on eight identical ridge points.
People v. Medina 59 Phil. 330
-
The first leading judicial decision in the Philippine Jurisprudence on the
Science of Fingerprinting.
The Eight Specific Patterns
No pattern area, no type lines= looking for an arch
1 area= loop
2 or more = whorl
General Characteristics of Arches
-
Arches are the simplest type of fingerprints that are formed by ridges that
enter on one side of the print and exit on the other
No deltas are present
1. Plain Arch
- The ridges enter upon one side
- Make a rise or wave at the center
-
And flow or tend to flow out upon the opposite side
Easiest pattern to recognize but it rarely appears
2. Tented Arch
- It possesses either an angle
- An upthrust or (type of ridge starting at a horizontal plain hitting the
pattern area), when it hits the very center only
- Two of the three basic characteristics of the loop (loop type)
3.
-
Loop
pattern in which one or more ridges enter upon either side
makes recurve
touch or pass an imaginary line between delta and core and pass out or
tend to pass out upon the side the ridge entered
complete loop (delta, core, imaginary line) if there are ridges that hit the
imaginary line
Elements of loop
-
sufficient recurve- the distance of the points (points where the ridges
curve are what we called SHOULDERS)
delta and core
ridge count- across a looping ridge
*no ridge count will fall to arch pattern (tented arch to be exact)
Recurving (Looping) Ridge
- a ridge that curves back in the direction in which it started
Sufficient Recurve
-
the space between shoulders of a loop, free of any appendage and
abutting right angle (when the appendage is spoiled(?) it is not
considered as sufficient recurve)
*the shoulders of a loop are the point at which the recurving ridge definitely
turns inward or curves
Appendage
-
a short ridge at the top or summit of a recurve usually at right angle
Process for fingerprints
-
analyzing
evaluation
verification
ULNAR/RADIAL
-
identify first if its left hand or right hand
*when a loop enters and exits form the THUMB side of the hand, the pattern will
always be a RADIAL LOOP
*when a loop enters and exit from the pinky finger, the pattern will always be an
ULNAR LOOP. There are NO exceptions to this rule.
The Whorl Family
-
these are patterns where ridges make a circuit resembling that of a
whirlpool
Essential Requisites
A pattern is a whorl I it complies with the ffg
-
at leat two deltas (maybe 3 for accidentals
at least one ridge make (or tend to make) a complete circuit (oval, spiral,
circular or any variant of a circle)
1.
-
Plain whorl
Consist of one or more ridges which make a complete circuit
With two deltas, between which
When an imaginary line is drawn ( at least one…
Finding delta- priority is bifurcation nearest to the core
No bifurcation= nearest obstruction to type line
2.
-
Central Pocket Loop
Consist of at least one recurving ridge
Or an obstruction at right angle
Difference from a plain whole- an imaginary line drawn from delta to
delta must not touch or cut a recurving ridge in front of the inner delta
*A recurving ridge, however, which has an appendage connected with it in the
line of flow and on the delta, side cannot be construed as a circuit ( the inner
line of flow is determined by drawing an imaginary line between the inner delta
and the center of the innermost recurve or looping ridge)
*an appendage connected at that point is considered to spoil the recurve on
that side
*pag loop imaginary line= delta to core
*pag whorl imaginary line= delta to delta
Line of flow
-
Is determined by drawing an imaginary line between the inner delta and
the center of the inner most recurving ridge
If the circuit is spoiled
-
In lieu of a recurve in front of the delta in the inner pattern area., an
obstruction ar right angle to the line of flow will suffice
3. Double Loop
- Consist of two separate loop formations with two separate and distinct
sets of shoulders and
- Two deltas
*the fact that there must be two separate loop formations eliminates from
consideration as double loop the “S” type core, the interlocking type core, and
the formation with one loop inside another= S and interlocking are considered
as plain whorl
*The loops of a double loop do not have to conform to the requirements of the
loop. In other words, no rage count is necessary
* the word separate as used here, does not mean unconnected. The two loops
may be connected by an appending ridge provided that it does not abut at
right angles between the shoulders of the loop formation
* the appendage rule for the loop applies also to the double loop
4. Accidental Whorl
- Consists of a combination of two different types of patterns with the
exception of the plain arch
- With two or more deltas or a pattern which possesses some of the
requirements for two or more different types
- Or a patter which conforms to NONE of the definitions



NO RIDGE COUNT= TENTED ARCH
ALWAYS CONSIDER THE OPENING OF THE BIFURCATION
When the tented arch is on top, it will be disregarded
*An accidental whorl consists of a combination of two different types of patters
with the exception of the plain arch, with two or more deltas or a pattern which
possesses some of the of the requirements for two or more different types or a
pattern which conforms to none of the definition.
Right thumb
-
Accidental
Loop
Tented arch
FINGERPRINT PATTERN RECOGNITION AND INTERPRETATION
GENERAL GROUP OF F.P. PATTERNS
The following are the three general groups of patterns as described by Sir
Francis Galton.
ARCHES – ridges flow from one side and make an exit to the other side.
LOOPS – ridges make a re-curve and goes back to the same side of origin.
WHORLS – ridges make a circuit
From the general sets of pattern, come the 8 specific patterns namely:
THE ARCH FAMILY (5%)
1. Plain Arch-60%
2. Tented Arch-40%
THE LOOP FAMILY (60%)
1. Radial Loop-6%
2. Ulnar Loop-94%
THE WHORL FAMILY (35%)
1.
2.
3.
4.
Plain Whorl-71%
Central Pocket Loop Whorl-13%
Double Loop Whorl-13%
Accidental Whorl-3%
-Ideally, before interpretation, identify first the pattern area and type lines.
- These make the classification of fingerprints easier since they are the ones
defining the actual extent of the patterns, hence making them the starting
points of classification.
WHAT IS A PATTERN AREA?
-
The pattern area is that part of a loop or whorl in which appear the cores,
deltas, and ridges with which we are concerned in classifying.
-
The pattern area is the only part of the finger impression with which we are
concerned in regard to interpretation and classification.
It is present in all patterns, of course, but in many arches and tented
arches it is impossible to define.
The pattern areas of loops and whorls are enclosed by type lines.
WHAT ARE TYPE LINES?
It may be defined as the two innermost ridges which start parallel, diverge, and
surround or tend to surround the pattern area.
***Lines A and B are the type
lines, point C is the Delta***
ARE TYPELINES ALWAYS CONSISTING OF TWO CONTINUOUS RIDGES?
-
No, Type lines ARE NOT ALWAYS two continuous ridges.
In fact, they are more often found to be broken.
When there is a definite break in a type line, the ridge immediately
outside of it is considered as its continuation.
(Examine the figure below)
***Sometimes type lines may be very short. Care
must be exercised in their location.
NOTA BENE:
When locating type lines it is necessary to keep in
mind the distinction between a divergence and a
bifurcation
A bifurcation is the forking or dividing of one line into two or more branches.
A divergence is the spreading apart of two lines which have been running
parallel or nearly parallel.
-
According to the narrow meaning of the words in fingerprint parlance, a
single ridge may bifurcate, but it may not be said to diverge. Therefore,
with one exception, the two forks of a bifurcation may NEVER constitute
type lines.
EXCEPTION:
-
When the forks run
parallel after
bifurcating and then
diverge. In such a case
the two forks become
the two innermost
ridges required by the
definition.
-
In the figure below, ridges A and B are two separate ridges that
converged. Therefore it cannot be used as the pair of the other type line
because the requirement must be two diverging lines. The correct type
lines are ridges C and D.
Remember this:
Angles are NEVER formed by a single ridge but by the abutting of one
ridge against another. Therefore, an angular formation cannot be used as
a type line.
THE FINGERPRINT PATTERNS
LOOP PATTERN
Definition: A loop is that type of fingerprint pattern in which one or more of
the ridges enter on either side of the impression; recurve, touch, or pass an
imaginary line drawn from the delta to the core; and terminate or tend to
terminate on or toward the same side of the impression from which such ridge or
ridges entered. Requirements of a loop:
A loop pattern must possess the following essentials:
• A delta and core
• A sufficient recurve
• One or more ridge count across a looping ridge
-
A sufficient recurve can be defined as that part of a recurving ridge
between the shoulders of a loop that is free of any appendages abutting
upon the outside of the recurve at right angles.
THE DELTA:
A delta may be:



Bifurcation— to be chosen, the bifurcation must open toward the
core. (PRIORITY CHOICE DELTA)
An abrupt ending ridge
A dot (TERTIARY CHOICE DELTA)



A short ridge (SECONDARY CHOICE DELTA)
A meeting of two ridges
A point on the first recurving ridge located nearest to the center
and in front of the divergence of the type lines.
RADIAL AND ULNAR LOOPS
1. The terms have been derived from radial and ulnar bones of the forearm.
a. Loops flowing in the direction of the little finger are ulnar loops.
b. Loops flowing in the direction of the thumb are radial loops.
i. Fingerprint cards
ii. Right hand: Position as on the hand
iii. Left hand: The reverse
c. For purposes of automated use, loops are termed either a right slanted
(those patterns where ridges flow to the right) or left slanted (those patterns
where ridges flow to the left).
2. Determining the direction of flow:
a. Begin at the core and follow or trace the ridges away from thedelta.
b. From the recurve to the open end of loop.
Other Issues Pertaining to Loops
1. Sufficient recurve: That part of a recurving ridge between the shoulders of a
loop. It must be free of any appendage abutting upon the outside of the
recurve at right angles.
2. If a ridge enters on one side of the impression, recurves, and passes an
imaginary line drawn between the delta and core but does not terminate on
the side from which it entered, but has a tendency to do so, the pattern is a
loop.
3. The recurve may take unusual forms.
4. The recurving ridge does not begin at the edge of the print, but possesses all
the requirements of the loop.
5. The recurving ridge enters from one side, recurves and turns back on itself. This
is a loop pattern.
PLAIN ARCH AND TENTED ARCH PATTERNS
The Plain Arch
-
Definition: The ridges enter on one side of the impression and flow or tend
to flow out the other with a rise or wave in the centre.
There may be various ridge formations such as ending ridges, bifurcations,
dots, and so forth, but they all tend to follow the general ridge contour.
The “crest” of an arch is the highest point reached by the rising friction
ridge. Most often that will be in the middle of the friction ridge.
The plain arch is also known as an absence of pattern (the plain arch has
no delta, no real core as in a loop, nor can a ridge tracing be conducted
as in a whorl pattern)
The Tented Arch
Definition: Most of the ridges enter on one side of the impression and flow
or tend to flow out on the other side, as in the plain arch; however, the ridge or
ridges at the centre do not.
There are three types of tented arches.
a. The type in which ridges at the center form a definite angle of 90 degrees or
less.
b. The type in which one or more ridges at the center form an upthrust.
- An upthrust is an ending ridge of any length rising at a sufficient degree
from the horizontal plane, that is, 45 degrees or more.
c. The type approaching the loop, possessing two of the three basic essential
characteristics, but lacking the third.



The mere converging of two ridges does not form a recurve,
without which there can be no loop.
The presence of the slightest upthrust at the center of the
impression is sufficient to make the pattern a tented arch.
The upthrust must be an ending ridge. It cannot be a
continuation of a curving ridge. Test for upthrust: If the ridges
on both sides of the ending ridge follow direction or flow
trend of the upthrust, the print may be classed as a P/A. If,
however, the ridges on only one side follow its direction, it is a
T/A.

An appendage or spike abutting upon a recurve at right
angles in the space between the shoulders of a loop on the
outside is considered to spoil the recurve.
THE WHORL PATTERN
Definition: A whorl is that type of pattern in which at least two deltas are
present with a recurve in front of each.
Types: The PLAIN WHORL, THE CENTRAL POCKET LOOP WHORL, THE DOUBLE LOOP
WHORL, AND THE ACCIDENTAL WHORL.
Plain Whorl
-
A plain whorl possesses two deltas and at least one ridge making a
complete circuit, which may be spiral, oval, circular, or any variant of a
circle'
1. The type lines for both deltas does not have to be the same ridge.
2. An imaginary line drawn between the two deltas must touch or cross at
least one of the recurving ridges within the inner pattern.
Central Pocket Loop Whorl
Combines the features of both loops and whorls.
1. The pattern looks like a loop but has a small whorl inside the loop ridges.
2. It has two deltas, one at the edge of the pattern area, and one inside
the pattern area just below the centermost ridges (inner delta).
3. It fulfills the requirements of the loop with one or more whorl ridges
around the core.
4. This pattern is sometimes called a bulb or flower for obvious reasons.
Definition: The central pocket loop has two deltas and at least one ridge
making a complete circuit, which may be spiral, oval, circular, or any variant of
a circle
1. One or more of the simple recurves of the loop type usually recurve a second
time to form a pocket within the loop (inside delta).
2. This does not have to be a continuation of the first ridge or connected to it.
Example: Loop convergence
a. An imaginary line between the inner and outer delta must not touch or
cross any of the recurving ridges within the inner pattern area.
b. In lieu of a recurve in front of the delta in the inner pattern area, an
obstruction at right angles to the line of flow will suffice.
c. The obstruction may be curved or straight, connected or unattached
to the recurve.
d. A dot cannot be considered an obstruction.
e. The inner line of flow is determined by drawing an imaginary line
between the inner delta and the center of the innermost recurve or
looping ridge.
f. A true recurving ridge does not have to cross the line of flow at right
angles; an obstruction does.
g. If the recurve or obstruction has an appendage at the point of
intersection of the line of flow, at the delta side, it is spoiled.
Double Loop Whorl
-
A double loop whorl is a pattern that consists of two separate loop
formations
with two separate and distinct sets of shoulders and two deltas (2 × 2 × 2)
1. The loops may be connected by an appendaging ridge provided that it does
not abut on the loop at right angles between the shoulders, spoiling it.
2. The loops do not have to conform to the ridge count requirement of a plain
loop.
3. It is not essential that both sides of a loop be of equal size or length.
4. It is not material from which side the loops enter. The loops may enter from
either side or both from the same side.
Accidental Whorl
-
An accidental whorl is a pattern consisting of a combination of two
different types of patterns, with the exception of the plain arch, with two
or more deltas, or a pattern which possesses some of the requirements for
two or more different types, or a pattern which conforms to none of the
definitions
If there is an issue between two types of patterns in the whorl pattern or ridges
which conform to more than one subdivision, the order of priority in preference
is:
1. Accidental
2. Double loop
3. Central pocket loop
4. Plain
RIDGE FORMATION
RIDGE CHARACTERISTICS/MINUTIAE OF FINGERPRINTS
THE GALTON’S DETAILS
1.
2.
3.
4.
5.
6.
7.
8.
BIFURCATION
BRIDGE
CROSSOVER
FRAGMENT
RIDGE ENCLOSURE
RIDGE ENDING
RIDGE HOOK/SPUR
SHORT RIDGE
BIFURCATION- single ridge which splits into two ridges, going side by side or
parallel to each other
RIDGE HOOK – ridge that divides to form two ridges; one connecting ridge
which splits at the side is extremely shorter than the other.
RIDGE ENDING – the termination of the ridge
RIDGE ENCLOSURE – is a ridge that divides to form two ridges which then rejoin
again to form a single ridge. (island/lake/eyelet)
SHORT RIDGE – a ridge of limited length
FRAGMENT – a ridge of extremely short length (not more than 3 mm)
BRIDGE– connects two adjacent ridges
CROSS OVER – the inter-lapping of two ridges against each other
OTHER TYPES OF RIDGE FORMATION
RECURVING RIDGE – is a ridge that curves back in the direction in which it
started.
CONVERGING RIDGES – two or more lines forming an angle, a ridge whose
closed end is angular and serves as a point of convergence.
DIVERGING RIDGES – two ridges running side by side and suddenly separating,
one ridges going one way and the other ridge, another way.
SUFFICIENT RECURVE – the space between shoulders of a loop, free of any
appendage, and abutting right angle.
APPENDAGE – a short ridge at the top or summit of a recurve usually at right
angle.
CORE – is a point on a ridge formation located at the center or heart of a
pattern.
DELTA OR TRI-RADIAL POINT – is a point on the ridge formation at or directly in
front or near the center of the divergence of the type lines.
ROD OR BAR – is a single ending ridge at the center of a recurving ridge of a
loop pattern.
ENVELOP - is a single recurving ridge enclosing one or more rods or bars.
STAPLE – single recurving ridge at the center of the pattern area.
CREASES – are thin, usually straight narrow white lines running transversely or
formed side to side, across the print, causing the puckering of the ridges.
INCIPIENT OR NASCENT RIDGE – this is a kind of ridge which is badly formed, thin,
short or broken which appear or appears in the depressions between two wellformed ridges.
FOCAL POINTS
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Within the pattern areas of loops and whorls are enclosed the focal points
which are used to classify them. These points are called delta and core.
The delta and core are the two most important points in classification
aside from the typelines and pattern area. These differentiate one pattern
from another pattern.
THE DELTA
-
-
It is otherwise known as “tri-radius”, “outer terminus”. It is the first
obstruction at or in front of and nearest the center of the point of
divergence of the type lines.
So to speak, the delta is obviously located at the point of divergence of
the two type lines.
The delta is comparable to the small island found in the middle of the
river which water flows towards the lake.
-
-
The island on the mouth of the river is known as the delta. Its shape
resembles that of the letter “D” (∆) in the Greek alphabet meaning
“Delta”.
The delta may appear in the pattern area in any of the following ridge
characteristics:
1.
2.
3.
4.
5.
6.
-
-
A bifurcation
A short ridge
An ending ridge
A convergence
A dot
A point in the first recurving ridge or a long ridge.
In figure below, the dot marked "delta" is considered as the delta
because it is the first ridge or part of a ridge nearest the point of
divergence of the two type lines.
If the dot were not present, point B on ridge C, as shown in the figure,
would be considered as the delta.
RULES IN DELTA SELECTION:
Rule 1. The Delta may not be located at the bifurcation which does not
open towards the core.
Rule 2. When there is a choice between a bifurcation and another type of
delta, the bifurcation selected.
Rule 3. If there are series of bifurcation opening towards the core, equally
close to the point of divergence of the type lines, the delta nearest to the
core shall be selected.
Rule 4. When there are two or more possible deltas which conform to the
definition, the one nearest the core is chosen.
Rule 5. The delta may not be located in the middle of a ridge running
between the type lines toward the core, but at the nearer end only.
-
THE CORE
It is otherwise known as the “inner terminus” and is known as the
approximate center of the fingerprint impression.
It will be necessary to concern ourselves with the CORE OF THE LOOP TYPE
ONLY. Whorl patterns do not require that the core be located so as the
family of arch pattern.
RULES IN CORE LOCATION
Rule 1. The core is placed upon or within the innermost sufficient recurve.
Rule 2. When the innermost sufficient recurve contains no ending ridge or rod
rising as high as the shoulders of the loop, the core is placed on the shoulder of
the loop farther from the delta.
Rule 3. When the innermost sufficient recurve
contains an uneven number of rods rising as high
as the shoulders, the core is placed upon the end
of the center rod whether it touches the looping ridge or not.
Rule 4. When the innermost sufficient recurve contains an even number of rods
rising as high as the shoulders, the core is placed upon the end of the farther
one of the two center rods, the two center rods being treated as though they
were connected by a recurving ridge.
RIDGE TRACING AND RIDGE COUNTING OF LOOPS AND WHORLS
RIDGE COUNTING
-
The process of counting the intervening ridges that touch or cross an
imaginary line drawn between the core and delta.
The number of ridges intervening between the delta and the core is
known as the ridge count.
***NOTE: It applies only to loops
GUIDELINES IN RIDGE COUNTING
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
An imaginary line is drawn between delta and the core.
Neither delta nor core is counted.
In the event there is a bifurcation of a ridge exactly at the point where the
imaginary line would be drawn, two ridges are counted.
Where the line crosses an island, both sides are counted.
Fragments and dots are counted as ridges only if they appear to be as
thick and heavy as the other ridges in the immediate pattern.
RIDGE TRACING
-
-
The method of ridge coursing using two deltas as the focal points.
The technique of whorl tracing depends upon the establishment of the
focal points—the deltas.
Every whorl has two or more.
When the deltas have been located, the ridge emanating from the lower
side or point of the extreme left delta is traced until the point nearest or
opposite the extreme right delta is reached.
The number of ridges intervening between the tracing ridge and the right
delta are then counted.
PROCEDURES:
1. Tracing always commences from the point of the left delta, but never on the
lower type line.
2. Tracing goes across the pattern following the lower contour of such pattern
till it ends at a relative point nearest to the right delta.
3. If the traced ridge ends, drop perpendicularly to a point on a ridge found
below and continue the tracing.
4. If the traced ridge reached the relative point nearest the right delta, and
goes above or inside it and there are three or more ridges intervening
between such ridge and the right delta = INNER WHORL Tracing (I)
5. If the traced ridge reached the relative point and goes above or below the
right delta with one or two ridges intervening between such delta and the
traced ridge, or if the traced ridge run directly to the right delta = MEETING
WHORL Tracing (M)
6. If the ridge traced passes outside (below) the right delta, and three or more
ridges intervene between the tracing ridge and the right delta, the tracing is
designated as an "OUTER WHORL” Tracing (O)
7. Whenever the ridge traced bifurcates, the rule for tracing requires that the
lower limb or branch proceeding from the bifurcation be followed.
8. Accidentals often possess three or more deltas. In tracing them only the
extreme deltas are considered, the tracing beginning at the extreme left
delta and proceeding toward the extreme right delta.
9. In a double loop or accidental the problem of where to stop tracing is
sometimes presented.
INTRODUCTION TO THE HENRY SYSTEM
-
-
-
As with any method of classification, the purpose of classifying fingerprints
is to establish a set protocol to utilize for searching, filing, and comparison
purposes.
This protocol provides an orderly method with which to go from the
general to the specific.
As an example, how would one begin to search for a fingerprint pattern if
that pattern has not been cataloged? Questions would certainly arise:
What type of pattern are we trying to locate?
Is the pattern a loop, whorl, or arch? Is there a specific flow to the
pattern? If the pattern is a loop, is it a large or small count loop flowing to
the left or to the right? If the pattern is a whorl, does it have an outer,
inner, or meet trace value? Some of these basic questions give us
direction to understand the need to have a method by which to search.
HENRY WITH FBI EXTENSION
-
One of the first, and certainly the most noted, of the classification systems
was a system named for Sir Edward Henry.
This identification system, when originally developed and implemented,
consisted of four parts:
-
-
-
PRIMARY, SECONDARY, SUB-SECONDARY, AND FINAL.
The system has since undergone changes and now includes an FBI (U.S.
Federal Bureau of Investigation) and the NBI (National Bureau of
Investigation) extension which changes the original configuration from
four to six categories.
There is a seventh if a second sub-secondary is used.
Since the introduction of technology and various automated fingerprint
identification (AFIS) systems, this method has come to be known as the
manual method.
In later parts of the lesson, AFIS systems are discussed.
As with any process that is newly introduced, with the Henry system of
classification being no exception, the need to practice and understand
the system is tantamount.
The current components of the Henry system are:
1. Key: The ridge count of the first loop appearing on the card, excluding little
fingers.
2. Major: The ridge count or trace value of the thumbs.
3. Primary: The numeric value of each finger containing a whorl pattern.
4. Secondary: Capital letter indicating the pattern of index fingers.
5. Sub-secondary: Values of counts and traces of loops and whorls of the index,
middle, and ring fingers.
6. Final: Ridge count of loops appearing on the little fingers.
An example of the form
of the Henry
classification appears
below:
FINGERPRINT CLASSIFICATION (THE HENRY SYSTEM)
CLASSIFICATION
-
The process of obtaining a formula for a set of fingerprint pattern where it
may be located in the filing cabinet
CLASSIFICATION FORMULA
-
The numerical description of a set of classified fingerprints which is
composed of figures and letters and written on a horizontal way like
fraction.
BLOCKING
-
It is the process of writing below each fingerprint pattern the
corresponding symbol of its name.
-
Where does the information come from for classification? The known
fingerprint card gives us the necessary information. Knowing how to read
and insert the appropriate information onto the fingerprint card is
important. The process whereby the information is inserted onto the card is
known as blocking.
-
Blocking the card consists of inserting the appropriate information
consisting of numbers, letters, and symbols in the appropriate places on
the card. Below is an example of layout and position of the fingers on the
fingerprint card.
Symbols used in Blocking:
A – plain arch
T – tented arch
R – radial loop ( / for right hand) ( \ for left hand)
U – ulnar loop ( / for left) ( \ for right hand)
W – plain whorl
C – central pocket loop whorl
D – double loop whorl
X – accidental whorl
AMP - Amputated
-
Note:
W – is used for all types of whorl but if the pattern is found on both INDEX,
individual sign is used.
/ - is used for loops but if found on both index, individual sign is used.
Based on the fingerprints and their interpretation, the following information
should be placed on the card in the appropriate places.
1. Index fingers—A, T, R, W, U as decided by the interpretation. Placed
under the index fingerprint. Note: A = arch, T = tented arch, R = radial
loop, W = whorl, U = ulnar loop ( \ / ).
2. Other fingers—Small letters as appropriate (i.e., a, t, r). Placed under all
fingerprints except index fingerprints.
3. Ulnar loops—Diagonal slash in the direction of flow.
4. Whorls—W where appropriate.
5. Counts or traces—In the upper right corner of the box.
6. Reference if necessary (giving an alternative).
DIVISION OF THE FINGERPRINT CLASSIFICATION (Henry System)






Primary classification
Secondary classification
Sub-secondary classification
Major classification
Final classification
Key classification
PRIMARY DIVISION
To begin the process of manual classification, one starts with the Primary.
-
Remember, the Primary is the numeric value of the finger where a whorl
appears.
Any type of whorl is assigned a value.
Ridge tracing does not enter into the primary classification.
The numeric value was established with the advent of the Henry system.
Whatever finger the whorl appears on, that finger assumes that value of
the square.
Upon adding up the numbers, always add 1 to the value (ARBITRARY)
(the numeric chart appears below).
Even number fingers, 2, 4, 6, 8, and 10 are registered above (numerator)
the classification line.
Odd number fingers 1, 3, 5, 7, and 9 are registered below (denominator)
the line.
The method of obtaining the primary can probably be shown best by
illustrations.
For example, assume that there is a whorl in the right index finger only. The value
of a whorl in this finger is 16. When 1 over 1 is added the resulting primary is 17
over 1. If a whorl appears in the right thumb and right index finger, the value is
16 over 16 plus 1 over 1 giving a primary of 17 over 17.
Steps in deriving the primary classification
1.
2.
3.
4.
By pairing
By assigning no. Values
By summing up the numbers
By adding the pre-established arbitrary count
Follow illustrations below:
SECONDARY DIVISION
The Secondary portion of the classification indicates the pattern type of the
index fingers and is always indicated by a capital letter.
A = arch
T = tented arch
R = radial loop
U = ulnar loop
W = whorl
-
The designation of the capital letters will always be right hand over left
hand on the classification line.
The secondary portion of the classification will be indicated by placing
the information immediately to the right of the primary classification.
There is also a secondary, small letter grouping.
-
Let us first look at the small letter groupings. Whenever an arch, tented
arch, or radial loop appears in other than the index fingerprints, those
patterns are indicated by a small letter:



Plain Arch= a
Tented Arch= t
Radial Loop=r
-
The small letter groups should appear next to the capital letter of the
secondary in the sequence in which they occur.
For example, if the fingerprint of an index finger is a whorl, and that of the
middle finger is a tented arch, the small t would then be placed to the
immediate right of the whorl in order of its appearance on the card.
If the thumb were an arch, for example, the small letter indicator would
then appear to the immediate left of the index finger.
In the secondary classification, the index finger can be seen as the
anchor and all small letter group patterns appear to the right or left of the
index finger.
-
-
When two or more of the small letters occur next to each other, it is indicated by
a number with the letter
Where there is a small letter group in the secondary, the sub-secondary and
major divisions are dispensed with. It should also be noted that approximately
7 to 10 percent of all patterns are small letter types.
Small letter groups can lend themselves to confusion. Remember, the small letter
groups are indicated in the classification where they appear on the card with
the index finger as the anchor indicated by a capital letter.
SUB-SECONDARY DIVISION
-
ridge counting in loops- inner or outer (IO)
Ridge tracing whorls- inner, meeting, outer(IMO)
* Index, middle and ring fingers excluding the little finger.
-
-
The Sub-secondary division of the classification is the grouping of ridge
count and/or whorl trace symbols for the index, middle, and ring
fingerprints appearing on the card.
For classification purposes, the right hand is indicated above the line, the
left hand is indicated below the line.
The sub-secondary division appears to the immediate right of the
secondary division on the card.
The sub-secondary is indicated by a letter.
To determine which symbol will be used to indicate the ridge count for a loop
pattern, a conversion of ridge counts into a letter must be done and that letter
placed onto the classification. The conversion chart is:
RIDGE COUNT CONVERSION
Index finger:
01 t • o 09 inner (I);
10+ outer (O)
Middle finger:
01 to 10 inner (I):
11+ outer (O)
Ring finger:
01 to 13 inner (I):
14+ outer (O)
Whorl ridge tracings are indicated by the value of the tracing:
(I) = Inner—3 or more ridges inside the right delta
(M) = Meet—0, 1, or 2 ridges inside or outside the right delta
(O) = Outer— 3 or more ridges outside the right delta
MAJOR DIVISION
Obtained by:
Ridge counting of loop patterns (SML)
Ridge tracing of whorl patterns (IMO)
Found in the THUMB only
LOOP MAJOR DIVISION
-
If found in both thumb of both hands, the ridges are counted and
compared to the table for loop division.
TABLE I - IF LEFT THUMB IS 16 or LESS
1-11 = small (S)
12- 16 = medium (M)
17 or more = large (L)
TABLE II- IF THE LEFT THUMB IS 17 OR MORE
*AUTOMATICALLY, THE DENOMINATOR IS LARGE (L)
1-17 = small (S)
18-22 = medium (M)
23 and above = large (L)
WHORL MAJOR DIVISION
-
If found on both thumbs of both hands
Ridges are traced and symbols I (inner), M (meeting), O (outer) are used
COMBINATION OF LOOP AND WHORL PATTERN DIVISION
- Ridge count the loop (SML symbols are used)
- Ridge trace the whorl (IMO symbols are used
FINAL DIVISION
FINAL CLASSIFICATION
The ridge count of the loops and whorls on the little fingers of both hands.
Arches are represented by a dash.
-
-
The final division may be placed above (numerator) the classification line
if the loop appears in the right little finger. If the loop appears in the left
little finger, the ridge count will be placed below (denominator) the
classification line.
The final cannot consist of both fingers; the final will consist of one or the
other.
In large whorl sections, whorls can also be counted but this is rare.
However, if a whorl is chosen to be included, there are rules that must be
adhered to.
The following rules apply when using whorls as the final.
• If the whorl appears on the right hand, • one counts from the left delta to the
core.
• If the whorl appears on the left hand, one counts from the right delta to the
core.
• If there are two cores, count from the delta to the core which is the fewest
number of ridges away.
• If the pattern is a double loop, count from the delta to the core of the upright
loop.
• If loops are horizontal, use the one nearest core.
KEY DIVISION
KEY CLASSIFICATION
It is the ridge count of the first loop pattern appearing on the fingerprint card
except for the two little fingers.
The key consists of the count of the first loop appearing on the card excluding
the little fingers. The little fingers are reserved for inclusion in the final. The
designation for the key is always indicated above the line farthest to the left on
the classification.
CLASSIFICATION OF SCARRED, AMPUTATED AND SIMILAR CONDITIONS
What happens if the prints one is taking are not clear and legible?
What happens if the pattern cannot be determined or if there are temporary or
permanent?
Injuries to the person being fingerprinted. How does one deal with these issues?
How does one classify these types of fingerprints? As with other aspects of the
Henry system, provisions have been made for just such occasions. The following
information addresses special issues related to fingerprints.
Classification of Scarred Patterns
When the following cannot be determined
Give
a. Pattern type and value ____________________________________Class of opposite
finger
b. Pattern only _____________________________________________Pattern of
opposite finger with actual value and reference
c. Count or Trace value ______________________________________Probable with
reference
d. Opposite fingers scarred __________________________________Meeting whorls
Classification of Amputated Fingers
Missing fingers
Class
a. One___________________________________________________ Same as opposite
with all references
b. Two or more___________________________________________ Same as opposite
with no references
c. Opposite ______________________________________________ Meet whorls
• Fingers missing at birth are treated as amputations
Classification of Bandaged and Unprintable Fingers
• One lacking—All references—opposite fingers.
• Two or more—Opposite class with no references.
• Opposites—Meet whorls.
• If pattern can be seen, it can be described. “Ulnar loop of about 9 ridge
count.”
• Make all possible attempts to print the individual when the injury is healed.
FINALS:
Known Fingerprints
In order to analyse friction ridge skin, one must first record the pattern digitally or
with fingerprint ink or powder. The resulting records are known as exemplars or
known prints. They are also known as inked prints, record prints, or standards.
Known fingerprints are recorded for four reasons:
1. To serve as an official record of a person’s identity
2. To search for a match to a prior arrest record
3. To compare to unknown, or latent, fingerprints
4. To input into the Automated Fingerprint Identification System (AFIS) for
subsequent searches
It is therefore important to take comprehensive records of the friction ridge skin
in order to provide the best possible exemplars for identification purposes.
-
Records of the friction ridge skin on the fingers, finger joints, palms, and
even feet and toes may be needed for identification.
Records of fingers, palms, the writer’s palm (side of the hand), and the
joints, tips, and sides of fingers are known as major case prints. The three
most common methods of recording friction ridges are inked impressions,
powdered impressions, and digital scans.
Inked Fingerprint Records
-
The most common medium for recording friction ridge skin is ink.
Inked fingerprints are recorded on tenprint cards.
Tenprint cards are 8″ × 8″ printed white cards formatted to official
government specifications.
-
-
A tenprint card, such as the card pictured in Figure 1, contains
demographic information along with the fingerprints of each of 10 fingers
(Figure 1).
Each finger is rolled in ink and subsequently rolled into the corresponding
box on the tenprint card.
The finger is rolled from “nail to nail” to capture the entire friction ridge
surface.
This means the finger must be rolled from one side of the finger (at the
nail) all the way around to the other side of the nail (Figure 2).
A fingerprint rolled from nail to nail should be roughly rectangular in shape
(Figure 3).
-
The fingerprints should be rolled with the individual standing slightly back
from the table with the arm bent at an approximate 90° angle.
-
When the thumb is rolled, the subject’s hand is rotated toward the body.
When the fingers are rolled, the subject’s hand is rotated away from the
body.
This allows the hand to be manipulated from the point of most to least
resistance.
The individual taking the fingerprints controls the subject’s hand to ensure
the most comprehensive fingerprint record is taken.
If the subject attempts to assist by moving his own fingers, the prints will be
smudged or incomplete.
-
-
-
The four fingers of the right hand and left hand are inked and recorded
simultaneously at the bottom of the tenprint card along with impressions
of the thumb.
These impressions are known as the flats, slaps, or plain impressions.
The flats of the four fingers together are placed in the section of the
tenprint card labeled “four fingers taken simultaneously.”
The sections for the flats of the thumbs are labeled “R. thumb” and “L.
thumb.”
It is important to record information here that may not be available in the
previously mentioned rolled prints, such as the ridge detail in the fingertips.
This is accomplished by lifting the thumb and fingers up to the tips when
the flats are inked and recorded.
Ink is the traditional medium for recording fingerprints, palm prints, and major
case prints. The following materials are used for recording fingerprints using ink
• Gloves
• Ink pad (or a light layer of ink rolled out onto a glass slab)
• Tenprint card
• Fingerprint card holder
• Re-tabs (correcting labels for if you make a mistake when rolling the
fingerprints)
• Hand cleaner/wet wipes
The process of collecting rolled fingerprint records in ink from a suspect is as
follows:
1. Set up the card in the card holder so the first row of boxes is clearly visible and
the card is secure.
2. Take control of the subject’s right hand.
3. Roll a thin layer of ink onto the right thumb (Figure 6).
4. Roll the right thumb onto the corresponding box on the tenprint card with
light, even pressure.
5. Repeat with the remaining fingers (Figure 7).
6. Record the flats by pressing the four fingers of the right hand lightly onto the
ink pad and rolling the fingers upward to ink the tips of the fingers (Figure 8).
7. Press the four fingers onto the flats section of the card with light pressure and
roll the fingers upward to record the tips of the fingers (Figure 9).
8. Press the right thumb lightly to the ink pad and roll the thumb upward to ink
the tip of the thumb.
9. Press the right thumb lightly to the area designated for the thumb flats and roll
the thumb upward to record the ridge detail on the tip of the thumb (Figure 10).
10. Repeat this procedure for the left hand.
It may also be necessary to record the palm of the subject. The palm is coated
with a light layer of ink and recorded on a white sheet of paper or a palm print
card as shown in Figure 11. The writer’s palm, the section of the meaty side of
the hand that rests on a surface when one holds a pen or pencil, is also
recorded. This area of the palm is known as the hypothenar.
FINGERPRINTS FROM DECEASED INDIVIDUALS
-
-
It is often necessary to collect postmortem exemplars from deceased
individuals for identification purposes.
In the case of the recently dead, fingerprint acquisition is a simple
process. Ink or powder may be used to record the fingerprints.
For inked fingerprints, postmortem print kits are available.
They include fingerprint strips and a postmortem record strip holder, often
referred to as a “spoon” (Figure 1).
This tool makes it easier to roll the fingerprints of the corpse laid out in a
supine position.
The Handprint System may also be used for recording postmortem friction
ridge skin.
The acetate sheet is cut into squares slightly larger than the finger to be
recorded. Each finger is powdered, recorded, and documented
individually (Figure 2).
There are several challenges to fingerprinting individuals who are in more
advanced stages of decomposition.
One challenge occurs when the subject is in rigor mortis.
Rigor mortis is the stiffening of the body, which can occur 2–4 h after
death and develops fully between 6 and 12 h postmortem (Figure 3).
Rigor mortis occurs when metabolism stops with the cessation of cellular
respiration after death.
Without adenosine triphosphate (ATP), the energy source for the body,
the muscles can no longer contract.
The deceased subject’s hands may be completely stiff and inflexible.
In this case, the rigor can be “broken” forcibly at each finger joint.
The fingers are then printed using ink or powder.
Decomposing friction ridge skin undergoing putrefaction, maceration, or
mummification presents a more challenging scenario.
Putrefaction is the breakdown of the cells of the human body after death
by bacteria and fungi.
Maceration occurs when skin is submerged in water and the tissues
become swollen.
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1 Friction ridge skin may loosen from the dermal layer.
Mummification occurs when the skin is dehydrated.
The friction ridge skin is dried, leathery, and shrivelled.
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Putrefied friction ridge skin is fragile (Figure4).
It may be moist and peeling off in layers.
Prior to attempting to ink or powder the finger, the area must be cleaned
and dried.
At this point, it may be possible to ink the finger and collect useable
fingerprints.
If the skin is separating from the dermis, the recorder may choose to
remove the skin and roll it with his gloved finger.
This must be done with great care since the decomposing skin is fragile
and tears easily.
If the skin is too badly decomposed for these techniques, the fingers can
be soaked in a 10% solution of formaldehyde.
Formaldehyde solution firms up the putrefied skin, after which it may be
recorded with ink or powder.
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Macerated skin may be swollen and wrinkled.
It may be possible to clean, dry, and record the fingerprints in the usual
manner using powder or ink.
If the skin is too wrinkled, it may be stretched slightly in order to record
more ridge detail.
Another option for dealing with wrinkled skin is to inject glycerine or a
product known as “tissue builder” under the skin.
This procedure puffs up the finger thus eliminating the wrinkles.
The liquid may leak, so it is recommended to tie a string or secure a rubber
band just above the injection site. If the skin is loosened from the dermis, it
may be recorded similar to the putrefied skin by removing it and placing it
on the recorder’s gloved hand for rolling with ink.
Mummified skin, also referred to as desiccated skin, and must be
rehydrated prior to recording with ink or powder (Figure 5).
The fingers can be severed from the hand and soaked in a 1%–3% solution
of sodium hydroxide or potassium hydroxide for 24–48 h.
If the skin is peeling, the outer layers can be removed gently under warm
running water with a soft-bristled toothbrush.
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1 If the skin is stiff, the fingers may be soaked for a further 24–48 h in a
solution of one tablespoon of dishwashing liquid in water.
When the skin is rehydrated, it is recorded using ink or powder.
Decomposed skin may also be recorded using white silicone casting
material.
Fingerprint powder is applied to the clean, dry finger.
The silicone casting material is mixed according to the manufacturer’s
directions and applied to the finger.
When it hardens, it can be gently peeled off the finger surface (Figure 6).
Regardless of the method utilized, great care should be exercised when
working with fragile skin.
Nature of Latent Fingerprints
With dramatic suddenness, he struck a match, and by its light exposed a
stain of blood upon the whitewashed wall. As he held the match nearer, I
saw that it was more than a stain. It was the well-marked print of a thumb.
Sherlock Holmes
Fingerprint Matrix
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Latent fingerprints are left on a surface when friction ridges coated with a
substance such as sweat or contaminants are deposited on a substrate or
surface.
This is analogous to an ink pattern left by a rubber stamp.
The rubber stamp is coated with ink, and the ink is pressed to a surface,
thereby duplicating the stamp pattern.
The substance coating friction ridges are made up mostly of sweat, but
may also be any combination of lotion, grease, soap, or anything else an
individual touched.
These substances are known collectively as the fingerprint matrix.
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The fingerprint matrix is predominantly comprised of sweat.
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An average of 2–4 L of fluid is secreted per hour from the sweat pores of
the body.
Most of the sweat evaporates.
Sweat is produced in coiled up glands in the skin (see figure below).
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A gland is a “tubular-shaped structure with a duct portion that coils in
helical fashion down deep into the dermis layer.”
The glands found in the friction skin, known as eccrine glands, form during
embryological development.
They develop between 8 and 32 weeks of fetal development.
There are three types of sweat glands in the human body that produce
three different types of sweat: apocrine, sebaceous, and eccrine.
Each of these glands is produced in different parts of the body.
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Apocrine sweat is found in the genital and armpit regions.
Sebaceous sweat is associated with regions of the body containing hair
follicles, including the face and scalp.
When the face or hair is touched, the friction ridges are coated with
sebaceous sweat.
The third type of sweat, eccrine sweat, is associated with friction ridge skin.
Eccrine sweat is secreted from pores found along the friction ridges of the
hands and feet.
There are 3–4 million eccrine sweat glands in the human body.
An individual doing strenuous exercise in a warm environment may
secrete up to 10 L of sweat from his eccrine glands.
Eccrine sweat is over 98% water.
The remaining components are excretory products including the following
organic and inorganic compounds: ammonia, magnesium, iodide,
bromide, fluoride, cobalt, manganese, sulfur, mercury, phosphate, sulfate,
iron, zinc, copper, lead, molybdenum, tin, urea, sodium lactate, proteins,
lipids, cholesterol/fatty acids, and 22 amino acids.
Sebaceous sweat, known as sebum, is secreted from pores associated
with hair follicles.
Sebum is composed of mostly lipids. De Paoli et al.
Identified more than 300 components of sebum in sebaceous fingerprints.
The lipid constituents include fatty acids, wax esters, squalene, and
cholesterol.
Latent fingerprints often contain a mixture of eccrine and sebaceous
sweat, but they also include other contaminants from surfaces touched
during the day.
Contaminants may include lotions, cosmetics, soap, or grease.
The composition of fingerprints is especially important when
determining which chemical reagent to use to visualize latent fingerprints.
Most fingerprint reagents react with amino acids, lipids, or sodium lactate.
Regardless of the chemical or physical development method used, latent
prints must be visualized to compare them with exemplars.
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Substrate
The substrate is the surface the latent print is deposited on. Substrates are
variable in texture and contour.
A substrate may be smooth or rough, flat or curved, porous or nonporous.
Porous surfaces are absorbent: permeable to gases or liquids.
Examples of porous surfaces include paper, cardboard, and unfinished
woods.
Nonporous items are non-absorbent. Examples of nonporous surfaces
include glass, plastic, or metal.
Rough or highly textured surfaces are not ideal for fingerprint collection
with chemical reagents or fingerprint powders.
When a latent fingerprint is deposited on a rough surface, such as the
grip of a gun or a window screen, the minutiae are not recorded in detail.
The pattern is interrupted by the texture of the surface.
When friction ridges come into contact with a nonporous item, a
fingerprint may be deposited on the surface.
It will stay on the surface unless it is wiped off or obliterated by
environmental or other physical forces. That makes fingerprints on
nonporous surfaces fairly fragile.
Both chemical reagents and fingerprint powders are used to develop
fingerprints on nonporous substrates.
Since fingerprints are mostly composed of sweat, they are easily
absorbed into porous substrates.
Therefore, they are more stable than latent prints deposited on
nonporous items.
These fingerprints are developed using chemical reagents that permeate
the substrate
Aging Latent Prints
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In some cases, an investigator may want to know how long the latent
fingerprint has been on a surface.
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For example, a fingerprint recovered from the interior of a stolen vehicle is
identified to a suspect.
The suspect insists he did not steal the car. Instead, he asserts he testdrove that exact car a year prior.
How can we test his assertion? Is it possible to “age” fingerprints or
determine how long they have persisted on a surface? As of present,
there is no scientific method for directly dating latent print residues.
Sometimes, it is possible to date a latent print indirectly because of the
circumstances in which it is deposited.
For example, a patent print left in the blood must have been made while
the source of the blood was still wet after the wound was made.
Thinly deposited blood will dry within minutes. In another example, a small
piece of broken glass at a crime scene is found to have the suspect’s
thumb on one side and index finger on the opposite side.
The only way that could happen is if the suspect picked up the fragment
after the glass was broken
There are many factors that contribute to how long a latent print will
persist on a surface, including the chemical composition of the latent
print, the nature and condition of the substrate, and the environment.
Immediately after a latent fingerprint is placed on a surface, it begins to
change.
The chemical compounds in sweat degrade.
There are hundreds of chemical compounds present in eccrine and
sebaceous excretory deposits.
The components and ratios of these compounds are unique to the
individual and are based on many different factors, including diet, age,
sex, health, metabolism, occupation, and stress.
The environmental factors that affect latent print persistence include
temperature, humidity, exposure to sunlight, and weather.
Surfaces may also have an impact on the persistence of latent prints.
Some of those variables include surface texture, cleanliness, shape,
porosity, and temperature.
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Research projects have focused on finding a stable component of latent
print residue and determining how the optical, electrostatic, and
chemical properties change over time.
Some of those components identified are saturated fatty acids and wax
esters.
Research continues in the area of aging latent fingerprints.
A challenge researcher’s face is the number of variables involved in this
process, only some of which are listed earlier.
However, new technologies with better sensitivity may allow researchers
to control for most of the aforementioned variables and find a nondestructive method of aging latent fingerprints on a surface.
DNA from Fingerprints
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Just like fingerprints, DNA recovered from crime scenes and evidentiary
items can be identified to an individual.
Advances in DNA analysis have made it possible to obtain DNA evidence
from items that have been touched, regardless of the substrate they are
deposited on.
Whether the substrate is rough or smooth, porous or nonporous,
fingerprints can be sampled for DNA.
This type of DNA is known as touch DNA.
Since the 1980s, samples of biological evidence from crime scenes have
been analysed for DNA.
Initially, biological material could only yield a DNA profile if the sample
size was 250 ng or more or visible to the human eye.
Over time, the technology and sensitivity of DNA analysis improved
allowing for the collection of smaller samples from crime scenes and
evidentiary items.
Biological evidence no longer needs to be visible to be collected for DNA
analysis.
When an individual touches a surface, skin cells are shed and may adhere
to the surface.
Humans shed tens of thousands of skin cells daily. Skin cells are invisible to
the naked eye.
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A sample with a mass of less than 100 pg can yield a DNA profile.15 (1 pg
is one-trillionth of a gram.)
Extensive research has shown that touch DNA can successfully
berecovered from latent fingerprints on various surfaces, as well as from
weapons, vehicles, clothing, wood, fabric, glass, briefcase handles, pens,
car keys, locker handles, telephone handsets, doorbells, chocolate bars,
electrical cords, knife handles, glass, gloves, paper, and other items.
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Touched surfaces that are rough or otherwise unsuited to preserving
fingerprint patterns are excellent sample areas for collecting touch DNA
evidence.
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Examples of unsuitable surfaces include textured gun and knife grips,
clothing, and rough, unfinished wood.
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These areas are swabbed with a wet sterile swab, the epithelial cells are
lifted from the material with adhesive tape, or the area is scraped with a
sterile razor blade (see figure below).
However, one does not have to choose whether to collect fingerprints or
DNA from a surface.
With the increased sensitivity of DNA, fingerprint examiners have the
option of swabbing latent fingerprints that have no value for
identification.
Any unusable, smudged, or poor quality fingerprint can be swabbed for
DNA with a sterile swab wetted with distilled water.
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Because touch DNA requires so little material to be viable, it is particularly
subject to contamination.
Even the act of breathing on an item can result in DNA transference.
Where it appears that DNA processing may be utilized, fingerprint
examiners and crime scene technicians must take great care to change
gloves frequently, wear particulate masks to cover the mouth and limit
the handling of evidentiary items.
Even the act of dusting a crime scene for fingerprints using a standard
fiberglass fingerprint brush and fingerprint powder may contaminate the
scene.
Disposable powder packets and fingerprint brushes are used to avoid
contamination.
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The analysis of touch DNA is not a common practice nor is it entirely
reliable.
Because of the minute amount of DNA present in touch samples, it is
subject to both false-positive and false-negative results.
It is also subject to contamination.
The vast majority of laboratories do not analyse touch DNA. However, as
research on the topic progresses, it may be used as an investigative tool
more frequently in the future.
FORENSIC LIGHT SOURCES
Bloodstains, semen, bruises, bone fragments, questioned documents,
flammable residues, fibres and fingerprints all merit examination with a
forensic light source or laser.
Visual Examination
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Light is one of the forensic scientist’s most potent tools.
Regardless of the substrate, matrix, or circumstance, all evidentiary items
and surfaces must be visually examined before any chemical or physical
process is initiated.
Visual examination is a non-destructive process. It allows visible fingerprints
to be documented before fingerprint powder or chemicals are applied.
A visual examination is not just performed under white overhead lights or
in natural lighting conditions.
A variety of light sources are used.
A simple flashlight can be used to shine light at various angles to create
light and shadow across a surface.
Oblique lighting is often the best way to see both latent, plastic, and
patent fingerprints on an object (see image below).
Light is shone at a low angle in order to see details on the surface where
light and shadow create contrast.
Oblique lighting is used throughout the forensic sciences to observe
details in shoe and tire impressions, firearm evidence, tool marks, and
various other types of evidence.
If a thorough visual examination of the surface reveals a fingerprint, that
print is photographed.
Only then may a fingerprint analyst proceed with chemical and physical
processing methods.
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Visual examination is a non-destructive process.
There are several other stages of fingerprint processing when the
fingerprint analyst uses light as a non-destructive technique to reveal
fingerprints.
Besides white light, the fingerprint analyst uses different colors of light,
ultraviolet (UV) light, and infrared light to view evidence without
obliterating fingerprints.
Physics of Light
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Forensic scientists use light of different colors to see details and view
luminescent chemical reagents.
Light is a form of electromagnetic energy that travels in waves.
Light energy is only one portion of a spectrum, or range, of wavelengths
that includes x-rays, gamma rays, and radio waves (see figure below).
Wavelengths are measured in nanometers (nm).
A wavelength can range from picometers (1 × 10–12 m) to many meters
in length (such as radio waves).
The shorter the wavelength of light, the greater the energy it produces.
The way humans perceive light and color is based on how light interacts
with matter.
When light hits a surface, it is reflected, transmitted, or absorbed by the
surface (see image below).
If it is absorbed, it is perceived as black in color.
Most of the light that passes through translucent or transparent objects is
transmitted.
Most of the light that is reflected bounces off a surface in different ways.
Depending on the texture and reflectivity of the surface, the human eye
sees that light as a color.
The spectrum of colors that makes up a rainbow is the same range of
wavelengths humans can perceive with the naked eye.
This range, known as the visible spectrum, contains light of wavelengths
between 390 and 700 nm.
Each color of the rainbow represents a short range of wavelengths within
the visible spectrum of light; for example, green light is between about 490
and 575 nm.
The color we see is a result of the wavelength of light reflecting off the
surface.
A red rose reflects light at wavelengths between 620 and 700 nm.
What we perceive as white light is in fact a mixture of colors.
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Black objects absorb light and therefore do not reflect light at a
wavelength within the visible color spectrum.
Fluorescence and Phosphorescence
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Each element in the periodic table has a unique atomic number.
The atomic number is the number of protons or electrons in an atom.
For example, oxygen has an atomic number of eight, indicating it has
eight protons and eight electrons.
Protons have a positive charge and electrons have a negative charge.
The charge is balanced in its ground, or normal, state.
The atomic mass is determined by the number of protons plus the number
of neutrons in the nucleus, the core of the atom.
Neutrons are neutral.
They have no charge. Isotopes are elements that have the same atomic
number but different numbers of neutrons and therefore different atomic
masses.
Light not only travels in waves but also acts on matter as a unit of energy
known as a photon.
A photon acts on surfaces at the atomic level.
An atom or molecule absorbs the photon’s energy and changes from its
natural ground state to a more energetic, “excited” state.
The atom is naturally inclined to seek its ground state.
In order to restore the balance of energy within the particle, it emits that
absorbed energy as a photon.
The energy absorbed and emitted by the particle is known as
electromagnetic radiation whether it is visible light, UV, infrared, x-ray,
microwaves, or radio waves.
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When the molecule absorbs energy, some of that energy is transferred to
surrounding molecules.
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Because some of the energy is used up in this process, the emitted
electromagnetic radiation has less energy than the absorbed
electromagnetic radiation.
As was mentioned earlier, light waves with longer wavelengths have lower
energy.
Light waves with shorter wavelengths have higher energy.
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When light is absorbed in one wavelength and loses energy as it interacts
with matter, the atom or molecule emits light at a longer wavelength than
the absorbed light.
This process creates luminescence.
Luminescence includes both fluorescence and phosphorescence.
When molecules are excited by a specific color, or wavelength, of light,
they luminesce in a way that is specific to the chemical composition of
that molecule.
Surfaces and chemicals that fluoresce will only glow when energy is
constantly applied to the surface.
For example, if a chemical fluoresces only under yellow light, it will stop
fluorescing as soon as that yellow light is removed. 1,8-diazafluoren-9-one
(DFO) and Rhodamine 6G are fluorescent chemicals that fluoresce under
green light (Figure 9.6).
When the green light is removed, the chemical no longer glows.
Phosphorescence occurs when the surface continues to glow even after
the energy source is removed.
Luminol is a chemical used to visualize latent bloodstains and enhance
patent bloodstains at crime scenes (see figure below). When the
chemical is sprayed onto a surface, it reacts with the iron in hemoglobin
and glows blue.
Luminol continues to glow on its own for approximately 30 s without
applying any constant energy source.
This phosphorescence is only visible in the dark.
Though phosphorescence is used in forensics, fingerprint analysts use
fluorescent compounds in the laboratory.
Fluorescence is most often not viewed with the naked eye.
The light that comes from the forensic light source is known as the incident
light.
When the incident light hits the substrate, it is reflected.
This is known as reflected light.
The angle at which the incident light hits the surface (the angle of
incidence) is equal to the angle at which it is reflected off the surface (the
angle of reflection).
When incident light hits the friction ridges that have been treated with
fluorescent chemicals or powders, the light bounces off from many
different angles.
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This light is known as scattered light.
A barrier filter is placed between the human eye and the surface.
The barrier filter blocks the reflected light, while the scattered light passes
through the filter and is perceived as fluorescence (see figure below).
Filters are often laboratory safety glasses of different colors that are
specific to the chemical reagent or powder, the color of the light source,
and the color of the fluorescent emission (see figure below).
Filters block the light source and only allow the fluorescing light from the
fingerprints to pass through. Yellow filters are used with blue light.
Fluorescent reagents are especially useful when the background
substrate is too dark or patterned to see the colored products of visible
reagents (see figure below). –
Fluorescence creates contrast, which is necessary in order to see minutiae
in the developed fingerprint.
However, if the substrate the fingerprint is placed on is itself fluorescent,
the fingerprint will not stand out against the background.
Forensic light sources are also useful tools for visualizing blood on various
surfaces.
Hemoglobin absorbs light energy.
Bloody fingerprints will therefore absorb long-wave UV light, some visible
and near-infrared light.
Because it absorbs light, the blood will appear black against the
background.
Blood can thus be enhanced through non-destructive means by simply
viewing it under various colors of light with various filters.
The blood should not be exposed to light energy for too long, as it may
degrade the DNA.
Colored glasses, or filters, are not only used to see the fluorescence.
They are also used to protect the eyes from electromagnetic radiation.
It is also important to protect the skin.
Any exposed skin should be covered with nitrile gloves and a long-sleeved
lab coat.
Higher energy, shorter-wavelength light is especially hazardous.
Therefore, great care should be taken especially when using shortwave
UV light.
Known Fingerprints
Known Fingerprints
In order to analyze friction ridge skin, one must first record the pattern digitally or
with fingerprint ink or powder. The resulting records are known as exemplars or
known prints. They are also known as inked prints, record prints, or standards.
Known fingerprints are recorded for four reasons:
1. To serve as an official record of a person’s identity
2. To search for a match to a prior arrest record
3. To compare to unknown, or latent, fingerprints
4. To input into the Automated Fingerprint Identification System (AFIS) for
subsequent searches
It is therefore important to take comprehensive records of the friction ridge skin
in order to provide the best possible exemplars for identification purposes.
Records of the friction ridge skin on the fingers, finger joints, palms, and even
feet and toes may be needed for identification. Records of fingers, palms, the
writer’s palm (side of the hand), and the joints, tips, and sides of fingers are
known as major case prints. The three most common methods of recording
friction ridges are inked impressions, powdered impressions, and digital scans.
Inked Fingerprint Records
The most common medium for recording friction ridge skin is ink. Inked
fingerprints are recorded on tenprint cards. Tenprint cards are 8″ × 8″ printed
white cards formatted to official government specifications. A tenprint card,
such as the card pictured in Figure 1, contains demographic information along
with the fingerprints of each of 10 fingers (Figure 1). Each finger is rolled in ink
and subsequently rolled into the corresponding box on the tenprint card. The
finger is rolled from “nail to nail” to capture the entire friction ridge surface. This
means the finger must be rolled from one side of the finger (at the nail) all the
way around to the other side of the nail (Figure 2). A fingerprint rolled from nail
to nail should be roughly rectangular in shape (Figure 3).
The fingerprints should be rolled with the individual standing slightly back from
the table with the arm bent at an approximate 90° angle. When the thumb is
rolled, the subject’s hand is rotated toward the body. When the fingers are
rolled, the subject’s hand is rotated away from the body. This allows the hand to
be manipulated from the point of most to least resistance. The individual taking
the fingerprints controls the subject’s hand to ensure the most comprehensive
fingerprint record is taken. If the subject attempts to assist by moving his own
fingers, the prints will be smudged or incomplete.
The four fingers of the right hand and left hand are inked and recorded
simultaneously at the bottom of the tenprint card along with impressions of the
thumb. These impressions are known as the flats, slaps, or plain impressions. The
flats of the four fingers together are placed in the section of the tenprint card
labeled “four fingers taken simultaneously.” The sections for the flats of the
thumbs are labeled “R. thumb” and “L. thumb.” It is important to record
information here that may not be available in the previously mentioned rolled
prints, such as the ridge detail in the fingertips. This is accomplished by lifting the
thumb and fingers up to the tips when the flats are inked and recorded.
Ink is the traditional medium for recording fingerprints, palm prints, and major
case prints. The following materials are used for recording fingerprints using ink
(Figure 4):
• Gloves
• Ink pad (or a light layer of ink rolled out onto a glass slab)
• Tenprint card
• Fingerprint card holder
• Re-tabs (correcting labels for if you make a mistake when rolling the
fingerprints)
• Hand cleaner/wet wipes
The process of collecting rolled fingerprint records in ink from a suspect is as
follows:
1. Set up the card in the card holder so the first row of boxes is clearly visible and
the card is secure (Figure 5).
2. Take control of the subject’s right hand.
3. Roll a thin layer of ink onto the right thumb (Figure 6).
4. Roll the right thumb onto the corresponding box on the tenprint card with
light, even pressure.
5. Repeat with the remaining fingers (Figure 7).
6. Record the flats by pressing the four fingers of the right hand lightly onto the
ink pad and rolling the fingers upward to ink the tips of the fingers (Figure 8).
7. Press the four fingers onto the flats section of the card with light pressure and
roll the fingers upward to record the tips of the fingers (Figure 9).
8. Press the right thumb lightly to the ink pad and roll the thumb upward to ink
the tip of the thumb.
9. Press the right thumb lightly to the area designated for the thumb flats and roll
the thumb upward to record the ridge detail on the tip of the thumb (Figure 10).
10. Repeat this procedure for the left hand.
It may also be necessary to record the palm of the subject. The palm is coated
with a light layer of ink and recorded on a white sheet of paper or a palm print
card as shown in Figure 11. The writer’s palm, the section of the meaty side of
the hand that rests on a surface when one holds a pen or pencil, is also
recorded. This area of the palm is known as the hypothenar.
Fingerprints from Deceased Individuals
It is often necessary to collect postmortem exemplars from deceased individuals
for identification purposes. In the case of the recently dead, fingerprint
acquisition is a simple process. Ink or powder may be used to record the
fingerprints. For inked fingerprints, postmortem print kits are available. They
include fingerprint strips and a postmortem record strip holder, often referred to
as a “spoon” (Figure 1). This tool makes it easier to roll the fingerprints of the
corpse laid out in a supine position. The Handprint System may also be used for
recording postmortem friction ridge skin. The acetate sheet is cut into squares
slightly larger than the finger to be recorded. Each finger is powdered,
recorded, and documented individually (Figure 2).
There are several challenges to fingerprinting individuals who are in more
advanced stages of decomposition. One challenge occurs when the subject is
in rigor mortis. Rigor mortis is the stiffening of the body, which can occur 2–4 h
after death and develops fully between 6 and 12 h postmortem (Figure 3). Rigor
mortis occurs when metabolism stops with the cessation of cellular respiration
after death.2 Without adenosine triphosphate (ATP), the energy source for the
body, the muscles can no longer contract. The deceased subject’s hands may
be completely stiff and inflexible. In this case, the rigor can be “broken” forcibly
at each finger joint. The fingers are then printed using ink or powder.
Decomposing friction ridge skin undergoing putrefaction, maceration, or
mummification presents a more challenging scenario. Putrefaction is the
breakdown of the cells of the human body after death by bacteria and fungi.
Maceration occurs when skin is submerged in water and the tissues become
swollen.1 Friction ridge skin may loosen from the dermal layer. Mummification
occurs when the skin is dehydrated. The friction ridge skin is dried, leathery, and
shriveled.
Putrefied friction ridge skin is fragile (Figure4). It may be moist and peeling off in
layers. Prior to attempting to ink or powder the finger, the area must be cleaned
and dried. At this point, it may be possible to ink the finger and collect useable
fingerprints. If the skin is separating from the dermis, the recorder may choose to
remove the skin and roll it with his gloved finger. This must be done with great
care since the decomposing skin is fragile and tears easily. If the skin is too badly
decomposed for these techniques, the fingers can be soaked in a 10% solution
of formaldehyde. Formaldehyde solution firms up the putrefied skin, after which
it may be recorded with ink or powder.
Macerated skin may be swollen and wrinkled. It may be possible to clean, dry,
and record the fingerprints in the usual manner using powder or ink. If the skin is
too wrinkled, it may be stretched slightly in order to record more ridge detail.
Another option for dealing with wrinkled skin is to inject glycerin or a product
known as “tissue builder” under the skin. This procedure puffs up the finger thus
eliminating the wrinkles. The liquid may leak, so it is recommended to tie a string
or secure a rubber band just above the injection site. If the skin is loosened from
the dermis, it may be recorded similar to the putrefied skin by removing it and
placing it on the recorder’s gloved hand for rolling with ink.
Mummified skin, also referred to as desiccated skin, must be rehydrated prior to
recording with ink or powder (Figure 5). The fingers can be severed from the
hand and soaked in a 1%–3% solution of sodium hydroxide or potassium
hydroxide for 24–48 h. If the skin is peeling, the outer layers can be removed
gently under warm running water with a soft-bristled toothbrush.1 If the skin is
stiff, the fingers may be soaked for a further 24–48 h in a solution of one
tablespoon of dishwashing liquid in water. When the skin is rehydrated, it is
recorded using ink or powder.
Decomposed skin may also be recorded using white silicone casting material.
Fingerprint powder is applied to the clean, dry finger. The silicone casting
material is mixed according to the manufacturer’s directions and applied to the
finger. When it hardens, it can be gently peeled off the finger surface (Figure 6).
Regardless of the method utilized, great care should be exercised when working
with fragile skin.
Learning Resources- Nature of Latent Fingerprints
With dramatic suddenness, he struck a match, and by its light exposed a stain of
blood upon the whitewashed wall. As he held the match nearer, I saw that it
was more than a stain. It was the well-marked print of a thumb.
Sherlock Holmes
Fingerprint Matrix
Latent fingerprints are left on a surface when friction ridges coated with a
substance such as sweat or contaminants are deposited on a substrate or
surface. This is analogous to an ink pattern left by a rubber stamp. The rubber
stamp is coated with ink, and the ink is pressed to a surface, thereby duplicating
the stamp pattern. The substance coating friction ridges are made up mostly of
sweat, but may also be any combination of lotion, grease, soap, or anything
else an individual touched. These substances are known collectively as the
fingerprint matrix.
The fingerprint matrix is predominantly comprised of sweat. An average of 2–4 L
of fluid is secreted per hour from the sweat pores of the body. Most of the sweat
evaporates. Sweat is produced in coiled up glands in the skin (see figure below).
A gland is a “tubular-shaped structure with a duct portion that coils in helical
fashion down deep into the dermis layer.” The glands found in the friction skin,
known as eccrine glands, form during embryological development. They
develop between 8 and 32 weeks of fetal development. There are three types
of sweat glands in the human body that produce three different types of sweat:
apocrine, sebaceous, and eccrine.
Each of these glands is produced in different parts of the body. Apocrine
sweat is found in the genital and armpit regions. Sebaceous sweat is associated
with regions of the body containing hair follicles, including the face and scalp.
When the face or hair is touched, the friction ridges are coated with sebaceous
sweat. The third type of sweat, eccrine sweat, is associated with friction ridge
skin.
Eccrine sweat is secreted from pores found along the friction ridges of the
hands and feet. There are 3–4 million eccrine sweat glands in the human body.
An individual doing strenuous exercise in a warm environment may secrete up
to 10 L of sweat from his eccrine glands. Eccrine sweat is over 98% water. The
remaining components are excretory products including the following organic
and inorganic compounds: ammonia, magnesium, iodide, bromide, fluoride,
cobalt, manganese, sulfur, mercury, phosphate, sulfate, iron, zinc, copper, lead,
molybdenum, tin, urea, sodium lactate, proteins, lipids, cholesterol/fatty acids,
and 22 amino acids.
Sebaceous sweat, known as sebum, is secreted from pores associated
with hair follicles. Sebum is composed of mostly lipids. De Paoli et al. identified
more than 300 components of sebum in sebaceous fingerprints. The lipid
constituents include fatty acids, wax esters, squalene, and cholesterol. Latent
fingerprints often contain a mixture of eccrine and sebaceous sweat, but they
also include other contaminants from surfaces touched during the day.
Contaminants may include lotions, cosmetics, soap, or grease.
The composition of fingerprints is especially important when determining
which chemical reagent to use to visualize latent fingerprints. Most fingerprint
reagents react with amino acids, lipids, or sodium lactate. Regardless of the
chemical or physical development method used, latent prints must be visualized
to compare them with exemplars.
Substrate
The substrate is the surface the latent print is deposited on. Substrates are
variable in texture and contour. A substrate may be smooth or rough, flat or
curved, porous or nonporous. Porous surfaces are absorbent: permeable to
gases or liquids. Examples of porous surfaces include paper, cardboard, and
unfinished woods. Nonporous items are nonabsorbent. Examples of nonporous
surfaces include glass, plastic, or metal.
Rough or highly textured surfaces are not ideal for fingerprint collection
with chemical reagents or fingerprint powders. When a latent fingerprint is
deposited on a rough surface, such as the grip of a gun or a window screen, the
minutiae are not recorded in detail. The pattern is interrupted by the texture of
the surface.
When friction ridges come into contact with a nonporous item, a
fingerprint may be deposited on the surface. It will stay on the surface unless it is
wiped off or obliterated by environmental or other physical forces. That makes
fingerprints on nonporous surfaces fairly fragile. Both chemical reagents and
fingerprint powders are used to develop fingerprints on nonporous substrates.
Since fingerprints are mostly composed of sweat, they are easily absorbed into
porous substrates. Therefore, they are more stable than latent prints deposited
on nonporous items. These fingerprints are developed using chemical reagents
that permeate the substrate (see figure below).
A fingerprint on a manila envelope developed using the chemical reagent
ninhydrin.
Aging Latent Prints
In some cases, an investigator may want to know how long the latent
fingerprint has been on a surface. For example, a fingerprint recovered from the
interior of a stolen vehicle is identified to a suspect. The suspect insists he did not
steal the car. Instead, he asserts he test-drove that exact car a year prior. How
can we test his assertion? Is it possible to “age” fingerprints or determine how
long they have persisted on a surface? As of present, there is no scientific
method for directly dating latent print residues.
Sometimes, it is possible to date a latent print indirectly because of the
circumstances in which it is deposited. For example, a patent print left in the
blood must have been made while the source of the blood was still wet after
the wound was made. Thinly deposited blood will dry within minutes. In another
example, a small piece of broken glass at a crime
scene is found to have the suspect’s thumb on one side and index finger on the
opposite side. The only way that could happen is if the suspect picked up the
fragment after the glass was broken
There are many factors that contribute to how long a latent print will persist
on a surface, including the chemical composition of the latent print, the nature
and condition of the substrate, and the environment. Immediately after a latent
fingerprint is placed on a surface, it begins to change. The chemical
compounds in sweat degrade. There are hundreds of chemical compounds
present in eccrine and sebaceous excretory deposits. The components and
ratios of these compounds are unique to the individual and are based on many
different factors, including diet, age, sex, health, metabolism, occupation, and
stress. The environmental factors that affect latent print persistence include
temperature, humidity, exposure to sunlight, and weather. Surfaces may also
have an impact on the persistence of latent prints. Some of those variables
include surface texture, cleanliness, shape, porosity, and temperature.
Research projects have focused on finding a stable component of latent
print residue and determining how the optical, electrostatic, and chemical
properties change over time. Some of those components identified are
saturated fatty acids and wax esters. Research continues in the area of aging
latent fingerprints. A challenge researchers face is the number of variables
involved in this process, only some of which are listed earlier. However, new
technologies with better sensitivity may allow researchers to control for most of
the aforementioned variables and find a nondestructive method of aging latent
fingerprints on a surface.
DNA from Fingerprints
Just like fingerprints, DNA recovered from crime scenes and evidentiary
items can be identified to an individual. Advances in DNA analysis have made it
possible to obtain DNA evidence from items that have been touched,
regardless of the substrate they are deposited on. Whether the substrate is rough
or smooth, porous or nonporous, fingerprints can be sampled for DNA. This type
of DNA is known as touch DNA. Since the 1980s, samples of biological evidence
from crime scenes have been analyzed for DNA. Initially, biological material
could only yield a DNA profile if the sample size was 250 ng or more or visible to
the human eye. Over time, the technology and sensitivity of DNA analysis
improved allowing for the collection of smaller samples from crime scenes and
evidentiary items. Biological evidence no longer needs to be visible to be
collected for DNA analysis.
When an individual touches a surface, skin cells are shed and may adhere
to the surface. Humans shed tens of thousands of skin cells daily. Skin cells are
invisible to the naked eye. A sample with a mass of less than 100 pg can yield a
DNA profile.15 (1 pg is one-trillionth of a gram.) Extensive research has shown
that touch DNA can successfully be
recovered from latent fingerprints on various surfaces, as well as from weapons,
vehicles, clothing, wood, fabric, glass, briefcase handles, pens, car keys, locker
handles, telephone handsets, doorbells, chocolate bars, electrical cords, knife
handles, glass, gloves, paper, and other items.
Touched surfaces that are rough or otherwise unsuited to preserving
fingerprint patterns are excellent sample areas for collecting touch DNA
evidence. Examples of unsuitable surfaces include textured gun and knife grips,
clothing, and rough, unfinished wood. These areas are swabbed with a wet
sterile swab, the epithelial cells are lifted from the
material with adhesive tape, or the area is scraped with a sterile razor blade
(see figure below). However, one does not have to choose whether to collect
fingerprints or DNA from a surface. With the increased sensitivity of DNA,
fingerprint examiners have the option of swabbing latent fingerprints that have
no value for identification. Any unusable, smudged, or poor quality fingerprint
can be swabbed for DNA with a sterile swab wetted with distilled water.
Because touch DNA requires so little material to be viable, it is particularly
subject to contamination. Even the act of breathing on an item can result in
DNA transference. Where it appears that DNA processing may be utilized,
fingerprint examiners and crime scene technicians must take great care to
change gloves frequently, wear particulate masks to cover the mouth and limit
the handling of evidentiary items. Even the act of dusting a crime scene for
fingerprints using a standard fiberglass fingerprint brush and fingerprint powder
may contaminate the scene. Disposable powder packets and fingerprint
brushes are used to avoid contamination.
The analysis of touch DNA is not a common practice nor is it entirely
reliable. Because of the minute amount of DNA present in touch samples, it is
subject to both false-positive and false-negative results. It is also subject to
contamination. The vast majority of laboratories do not analyze touch DNA.
However, as research on the topic progresses, it may be used as an
investigative tool more frequently in the future.
Learning Resources- Forensic Light Sources
Bloodstains, semen, bruises, bone fragments, questioned documents, flammable
residues, fibers and fingerprints all merit examination with a forensic light source
or laser.
Visual Examination
Light is one of the forensic scientist’s most potent tools. Regardless of the
substrate, matrix, or circumstance, all evidentiary items and surfaces must be
visually examined before any chemical or physical process is initiated. Visual
examination is a non-destructive process. It allows visible fingerprints to be
documented before fingerprint powder or
chemicals are applied.
A visual examination is not just performed under white overhead lights or
in natural lighting conditions. A variety of light sources are used. A simple
flashlight can be used to shine light at various angles to create light and shadow
across a surface. Oblique lighting is often the best way to see both latent,
plastic, and patent fingerprints on an object (see image below). Light is shone at
a low angle in order to see details on the surface where light and shadow
create contrast. Oblique lighting is used throughout the forensic sciences to
observe details in shoe and tire impressions, firearm evidence, tool marks, and
various other types of evidence.
If a thorough visual examination of the surface reveals a fingerprint, that
print is photographed. Only then may a fingerprint analyst proceed with
chemical and physical processing methods. Visual examination is a nondestructive process. There are several other stages of fingerprint processing
when the fingerprint analyst uses light as a non-destructive technique to reveal
fingerprints. Besides white light, the fingerprint analyst uses different colors of
light, ultraviolet (UV) light, and infrared light to view evidence without
obliterating fingerprints.
Physics of Light
Forensic scientists use light of different colors to see details and view luminescent
chemical reagents. Light is a form of electromagnetic energy that travels in
waves. Light energy is only one portion of a spectrum, or range, of wavelengths
that includes x-rays, gamma rays, and radio waves (see figure below).
Wavelengths are measured in nanometers (nm). A wavelength can range from
picometers (1 × 10–12 m) to many meters in length (such as radio waves). The
shorter the wavelength of light, the greater the energy it produces.
The color spectrum (the range of colors visible to the human eye) is a narrow
range of wavelengths within the
electromagnetic spectrum.
The way humans perceive light and color is based on how light interacts with
matter. When light hits a surface, it is reflected, transmitted, or absorbed by the
surface (see image below). If it is absorbed, it is perceived as black in color.
Most of the light that passes through translucent or transparent objects is
transmitted. Most of the light that is reflected bounces off a surface in different
ways. Depending on the texture and reflectivity of the surface, the human eye
sees that light as a color.
A schematic drawing demonstrating how light is reflected, absorbed, and/or
transmitted
when it interacts with a surface.
The spectrum of colors that makes up a rainbow is the same range of
wavelengths humans can perceive with the naked eye. This range, known as
the visible spectrum, contains light of wavelengths between 390 and 700 nm.
Each color of the rainbow represents a short range of wavelengths within the
visible spectrum of light; for example, green light
is between about 490 and 575 nm. The color we see is a result of the wavelength
of light reflecting off the surface. A red rose reflects light at wavelengths
between 620 and 700 nm. What we perceive as white light is in fact a mixture of
colors. Black objects absorb light and therefore do not reflect light at a
wavelength within the visible color spectrum.
Fluorescence and Phosphorescence
Each element in the periodic table has a unique atomic number. The
atomic number is the number of protons or electrons in an atom. For example,
oxygen has an atomic number of eight, indicating it has eight protons and eight
electrons. Protons have a positive charge and electrons have a negative
charge. The charge is balanced in its ground, or normal, state. The atomic mass
is determined by the number of protons plus the number of neutrons in the
nucleus, the core of the atom. Neutrons are neutral. They have no charge.
Isotopes are elements that have the same atomic number but different numbers
of neutrons and therefore different atomic masses.
Light not only travels in waves but also acts on matter as a unit of energy
known as a photon. A photon acts on surfaces at the atomic level. An atom or
molecule absorbs the photon’s energy and changes from its natural ground
state to a more energetic, “excited” state. The atom is naturally inclined to seek
its ground state. In order to restore the balance of energy within the particle, it
emits that absorbed energy as a photon. The energy absorbed and emitted by
the particle is known as electromagnetic radiation whether it is visible light, UV,
infrared, x-ray, microwaves, or radio waves.
When the molecule absorbs energy, some of that energy is transferred to
surrounding molecules. Because some of the energy is used up in this process,
the emitted electromagnetic radiation has less energy than the absorbed
electromagnetic radiation. As was mentioned earlier, light waves with longer
wavelengths have lower energy. Light waves with shorter wavelengths have
higher energy. When light is absorbed in one wavelength and loses energy as it
interacts with matter, the atom or molecule emits light at a longer wavelength
than the absorbed light (Figure 9.5). This process creates luminescence.
Luminescence includes both fluorescence and phosphorescence. When
molecules are excited by a specific color, or wavelength, of light, they
luminesce in a way that is specific to the chemical composition of that
molecule. Surfaces and chemicals that fluoresce will only glow when energy is
constantly applied to the surface. For example, if a chemical fluoresces only
under yellow light, it will stop fluorescing as soon as that yellow light is removed.
1,8-diazafluoren-9-one (DFO) and Rhodamine 6G are fluorescent chemicals that
fluoresce under green light (Figure 9.6). When the green light is removed, the
chemical no longer glows.
Fluorescence is observed when light is absorbed, loses energy as it interacts with
matter, and is emitted at a longer wavelength.
A fingerprint developed with Rhodamine 6G.
Phosphorescence occurs when the surface continues to glow even after
the energy source is removed. Luminol is a chemical used to visualize latent
bloodstains and enhance patent bloodstains at crime scenes (see figure
below). When the chemical is sprayed onto a surface, it reacts with the iron in
hemoglobin and glows blue. Luminol continues to glow on its own for
approximately 30 s without applying any constant energy source. This
phosphorescence is only visible in the dark. Though phosphorescence is used in
forensics, fingerprint analysts use fluorescent compounds in the laboratory.
The bathroom floor at a crime scene (a) before and (b) after treatment with
luminol.
Fluorescence is most often not viewed with the naked eye. The light that
comes from the forensic light source is known as the incident light. When the
incident light hits the substrate, it is reflected. This is known as reflected light. The
angle at which the incident light hits the surface (the angle of incidence) is
equal to the angle at which it is reflected off
the surface (the angle of reflection). When incident light hits the friction ridges
that have been treated with fluorescent chemicals or powders, the light
bounces off from many different angles. This light is known as scattered light. A
barrier filter is placed between the human eye and the surface. The barrier filter
blocks the reflected light, while the scattered light passes through the filter and is
perceived as fluorescence (see figure below).
This schematic demonstrates how incident light from a fluorescent light source
interacts with a latent print treated with a fluorescent chemical reagent. The
incident light
reflects off the surface and is observed through the barrier filter as fluorescence.
Filters are often laboratory safety glasses of different colors that are
specific to the chemical reagent or powder, the color of the light source, and
the color of the fluorescent emission (see figure below). Filters block the light
source and only allow the fluorescing light from the fingerprints to pass through.
Yellow filters are used with blue light. Fluorescent reagents are especially useful
when the background substrate is too dark or patterned to see the colored
products of visible reagents (see figure below). Fluorescence creates contrast,
which is necessary in order to see minutiae in the developed fingerprint.
However, if the substrate the fingerprint is placed on is itself fluorescent, the
fingerprint will not stand out against the background.
Ninhydrin fingerprints developed on a check.
Forensic light sources are also useful tools for visualizing blood on various
surfaces. Hemoglobin absorbs light energy. Bloody fingerprints will therefore
absorb long-wave UV light, some visible and near-infrared light. Because it
absorbs light, the blood will appear black against the background. Blood can
thus be enhanced through nondestructive means by simply viewing it under
various colors of light with various filters. The blood should not be exposed to light
energy for too long, as it may degrade the DNA.
Colored glasses, or filters, are not only used to see the fluorescence. They
are also used to protect the eyes from electromagnetic radiation. It is also
important to protect the skin. Any exposed skin should be covered with nitrile
gloves and a long-sleeved lab coat. Higher energy, shorter-wavelength light is
especially hazardous. Therefore, great care should be taken especially when
using shortwave UV light.
Module Content
In choosing which technique to use in the development of latent fingerprints,
one must utilize sequential processing. This means that the least intrusive method
is applied first through to the most intrusive. As an example, the least intrusive
method is visual examination, using inherent lighting followed by illumination with
oblique lighting. The most intrusive would be a dye stain or other chemical
technique. Those prints seen without treatment (plastic and patent) should be
photographed and, where appropriate, removed from the scene. When
photographing, take a photograph with and without a scale of the prints and
object. The preferred scale is an ABFO, L scale. To assist in the detection of
semihidden prints, oblique, infrared, or ultraviolet lighting may be utilized.
Moisture from
the breath can also assist in the detection of the prints, as the moisture adheres
to the prints. Prints on nonabsorbent, hard surfaces will remain entirely on the
surface in the form of a delicate liquid or semisolid deposit consisting mainly of
water and oil, extending upward from the surface, which makes an ideal
adhesive base for fingerprint powders. Whenever there is a potential of losing
the latent print during the lifting or retrieval process, that latent should be
photographed.
The following development techniques are not all-encompassing but rather an
example of the more common techniques used in the development process.
To learn and understand all of the possible methods for development, one must
invest many hours in training and practice to perfect the techniques.
Powder Techniques
I. Brush and Fingerprint Powder Development (Figure 1). This is the most common
method of developing latent prints currently in use.
A. Materials: Fingerprint powder, fiberglass brush, or camel or squirrel hair brush,
lifting tape, latent lift cards, and writing implement.
B. Method:
1. Apply a small amount of powder to an area with the brush.
2. As a latent pattern becomes visible, the brush strokes follow the print ridge
contour. Try to clean the powder from the valleys to make print clearer.
3. The print is then lifted with the tape onto the card or covered with tape and
left on the surface of the object.
Cautions: Brush gently. Some latent prints will be easily dissipated. Use small
amounts of powder, as it is much easier to add powder than to brush away
excess powder. Ensure the surface is completely dry when using powder. If not,
the powder will become muddy, smear the print, and ruin the brush.
4. Complete the face of the card with the appropriate information: Case/report
number; type of offense; location of crime; name of investigator; time of lift;
date of lift; object lifted from; location of print on object. Note: An illustration
(sketch) should be made next to the lift on the card.
II. Magnetic Powder Development. This technique is generally not good for prints
on metal surfaces or magnetic tapes as the magnet may erase information.
A. Materials: Magnetic wand, magnetic particles mixed with powder, lifting
tape, latent lift cards, and writing implement.
B. Method: This method is used in a similar fashion as brush and powder.
However, the magnetic wand should not touch the surface. The magnetic
powder is the only part that should be applied to the surface. The magnetic
wand may cause scratches on a surface and degrade or contaminate latent
prints.
Note: There are a variety of powders that may be utilized to develop prints on
various surfaces. The most common powders are black, white, and bichromatic.
Some powders may also be used in conjunction with other chemical techniques
such as cyanoacrylate ester (CAE, or Super Glue). The reason for the variety of
powders is to provide the greatest contrast with the background on which the
fingerprint is developed.
Chemical Techniques
Utilizing various chemicals to develop latent fingerprints allows the investigator
the ability to potentially develop prints on any surface if the conditions
are right. Which technique to utilize will be dictated by the knowledge and
experience of the investigator, as well as the item or surface to be processed.
What must be emphasized is that utilizing a specific technique may produce
different results in different environments.
When attempting to develop latent prints, there are no absolutes. Remember,
latent prints are chance impressions on a surface. Chemical reactions are a
result of substances contained in the perspiration or on the friction skin being
transferred from the friction skin ridges to the object. Chemicals such as salt
(chloride), protein, amino acids, lipids, and oil react with the chemicals to reveal
the latent prints. Other substances might include blood, grease, or food stuffs.
Fluorescent Powders These powders may be used in place of traditional
powders or in conjunction with other techniques such as Super Glue. These
powders tend to be much finer and produce the best results when used with a
feather duster rather than the traditional fiberglass or camel hair brush. The
advantage to this technique is that, due to the fine powder composition, less
activity is required to develop latent prints, thus lessening the likelihood of
destruction of the print. The disadvantage is that with this technique additional
luminescence is required in the form of an alternate light source (ALS) or light
amplification by stimulated emission of radiation (laser) to make the print usable.
Lights with a filter barrier may be used to detect the prints in lieu of the ALS or
laser. The prints developed with this method must also be photographed. These
powders may be used just as traditional powders are.
Cyanoacrylate Ester. This technique may be used in two methods, the fuming
chamber (Figure 2) or tenting method, or with a wand. CAE reacts
with the amino acids and fatty acids in the perspiration to form a white colored
polymer. Contrast may be enhanced through the use of a variety of powders
or dye stains applied to the developed polymer. Commonly, fluorescent
powders and dye stains are applied on surfaces where the contrast is less than
desirable. An ALS or laser is then used to enhance the print, after which the print
is photographed. This method may be applied to metal, glass, plastic,
garbage bags, electrical tape, and many other nonporous surfaces.
Caution: When using the CAE method, caution is paramount. This chemical has
the same effect as tear gas and may aggravate the mucous glands
and membranes.
Fuming or Tenting Method. Place the specimen, preferably suspended, into a
fuming chamber. This allows for the vapors to evenly adhere to the surface(s)
of the items. Place ten to twelve drops of liquid CAE into a pipette or aluminum
dish that is sitting atop a hotplate or heating device. Heat the CAE, and
the vapors should become visible. Where a prepackaged envelope of CAE will
be used, simply open the envelope and allow the CAE to disperse into the
chamber. Allow the item to remain in the chamber for a minimum of one to two
hours. This will allow the CAE to set onto the specimen. To enhance the
development process, humidity should be present. Where a chemical reactive
process is used, such as sodium hydroxide, place the item to be processed into
the chamber. Place cotton treated with sodium hydroxide into an aluminum
dish; then add several drops of CAE to the sodium hydroxide-treated cotton.
The reaction should be immediate and the vapors will quickly appear. A word of
caution, this technique generates a great deal of heat. Some type of hot pad
or aluminum should be place under the cotton to prevent heat damage. To
enhance an even dispersal of CAE, a fan should be in the chamber to provide
circulation. The fan does not need to be set on high. The purpose is simply to
allow the vapors to disperse throughout the chamber. Where there is a large
chamber to be processed, a room or vehicle, the investigator should take the
appropriate action to ensure the least amount of contamination occurs.
CAE Wand Method. This method is not as controlled as the chamber method.
More care and caution must be exercised. Proper respiratory
equipment must be used to prevent contamination. This method is not
suggested when processing a premises. Simply pass the wand over the
areas where the suspected fingerprints might be. The prints should quickly
develop into a white film on the surface of the item. The fingerprints may
then be photographed or further enhanced with the addition of powders. It is
suggested that a short period of time (ten to twenty minutes) be allowed
to elapse before applying the powder. This will allow the CAE prints to set onto
the surface.
Iodine Fuming The two most common methods by which this technique may be
utilized are the iodine fuming gun (most common) and the fuming
cabinet. Two other less used techniques are iodine dusting and iodine solution.
When applied, the iodine is absorbed by the fingerprint secretion,
which produces a dark brownish to blackish appearance. It is thought that the
iodine reacts with fatty acids and lipids contained in the fingerprint. This
technique is used for paper and may be used on human skin. This technique is
very corrosive and may pose safety issues when improperly applied. The
resulting prints that develop must be photographed as the prints tend to fade
over time. Fixatives may be applied to iodine-developed prints to prolong
their appearance.
Fuming Gun. Constructing a fuming gun requires a glass or hard plastic tube with
a small rubber hose used as a nozzle applicator. Iodine crystals, glass wool,
and calcium chloride are placed into the gun. To activate the iodine, blow into
the mouthpiece and move the nozzle or rubber hose over the object where
fingerprints are thought to be. The heat from the breath will activate the
chemicals. When the fingerprints develop, they should be noted and
photographed as soon as possible to prevent the possibility of loss. Upon
completion of the technique, the equipment should be cleaned as soon as
possible to prevent corrosion.
Fuming Cabinet. Suspend the items to be treated in a cabinet at the upper
portion. Place the iodine crystals in a clean evaporating dish inside the
cabinet. Close the door to the cabinet. The crystals are then heated within the
cabinet. Keep the items in the cabinet under observation to monitor the
development of latent prints. When maximum contrast has been achieved,
remove the remaining crystals from the cabinet. Then remove the items
from the cabinet and, as soon as possible, photograph the prints on the item.
Ninhydrin Method Ninhydrin is a solution that may be applied by using a spray,
swabbing, or dipping method. Ninhydrin may be commercially purchased
or can be prepared by the investigator. Ninhydrin reacts with the amino acids,
peptides, and protein contained in the print. This chemical is used on items such
as paper, cardboard, and unfinished wood. The reaction of the chemical
produces what has been termed Ruhemann’s purple. This is a pinkish/purple
color print that appears on the item revealing the presence of fingerprints. The
processing of an item with this method should be completed in a controlled
laboratory setting. Appropriate breathing apparatus and proper ventilation
should be utilized as well as thick rubber gloves. This
chemical should not be inhaled, nor should the chemical be allowed to contact
the skin. The preferred method of application of this chemical is by dipping or
swabbing. This alleviates the possibility of accidental inhalation. To enhance or
provide optimal development of ninhydrin prints, the item should be placed in a
chamber where the temperature and humidity are sufficient. The desired
temperature is approximately 80°F, with a humidity rate of approximately 80
percent.
Procedure After Developing Prints
1. Photograph where appropriate. The photos should be done with and without
a scale. The best type of scale is the ABFO, L type of
scale. Overalls of the item where the print was developed should be taken, as
well as close-ups showing the print itself. If possible, a
one-to-one photo should be taken.
2. Upon completion of the photography, the decision must be made whether
the entire item will be taken or whether the print will be lifted
from the item. When appropriate, the entire item or object should be retained
for use in court. Note: Remember, the print is the evidence,
not necessarily the surface that the print was developed from.
3. Where a lift is made and placed onto a latent fingerprint lift card,
the following information should be present:
a. Case/report number
b. Date/time
c. Scene address
d. Person making the lift
e. Type of object
f. Place of lift (Note: A sketch should be made on the card near the lift)
4. Take elimination prints from victims, and witnesses where appropriate.
5. Care and transportation of the evidence:
a. Ensure the chain of custody is recorded to provide accountability.
b. If items need to be secured, ensure proper securing of the item’s by top and
bottom, or in a place least likely to damage the item or fingerprints.
Module Content 2
TECHNIQUES OF LATENT PRINT DEVELOPMENT



Physical Method/Mechanical Method
o The principle involved is that the developing reagents will
adhere or stick to the sweats that are present in the latent
print.
Chemical Method/Liquid Method
o The principle involved is that when the developing reagent
comes in contact with the chemical composition of the
sweat another chemical element is formed or there is a
chemical reaction that takes place.
Gas Method/Fuming Method
o Fumes of the reagent will react with certain components of
the sweat.
SURFACE TYPES

o
o
o
o
Porous - Absorbent: paper, cardboard, wood, other cellulose
Non-porous - Repel moisture, polished: glass, metal, plastics,
lacquered or painted wood, rubber
Semi-porous - Glossy cardboard, finished wood, glossy
magazine covers
Textured- pebbled plastic surfaces of appliances
CONSIDERATIONS PRIOR TO RECOVERING LATENT PRINTS

o
o
o
o
o
Safety of the personnel at the scene
Surface type to be processed
Surface exposed to water or not?
Availability of equipment
Exposure of the surface to extreme heat?
PHYSICAL METHODS OF DEVELOPING

POWDERS
Adhere to both water and fatty deposits. Generally useful on newer prints.
Choose powder to contrast with background. Useful on dry, relatively smooth,
non-adhesive surfaces. Used after laser fluorescence. Used before Ninhydrin and
after Cyanoacrylate. Results may vary with skill. Photograph or lift by
conventional methods.
KINDS OF POWDERS
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Regular (carbon black, flake metal)
Magnetic (light, dark, fluorescent)
Fluorescent (powder with fluorescent dye stain)
Bichromatic (reflective aluminum powder and black powder)
Early local ingredients:
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Charcoal, lead powder, cigar ashes, powdered iron, soot, talc
Harmful: lead, mercury, cadmium
FLUORESCENT POWDERS
Offer advantages conventional powders don't, but applied the same.
Photograph or lift by conventional methods. Useful on confusing or multi-colored
backgrounds. UV or forensic light required.
BRUSHES
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o
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Animal hair
Fiberglass filaments
Feathers
Magnetic applicator
TECHNIQUES USING POWDERS
DUSTING
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Appropriate Surface:
o Ridged/non-porous such as glass, plastic, or metal
Theory:
o Dust will adhere to sweat & oils left behind
CHEMICAL METHODS
NINHYDRIN
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Appropriate Surface:
o porous such as paper, tissue, and clothing
Theory:
o ninhydrin reacts with amino acids to form a purple
compound
AgNO3 & UV LIGHT

Appropriate Surface:
o porous such as paper or drywall
o Theory:
o When exposed to ultra-violet (UV) light, silver nitrate reacts
with the salt in sweat to form a blackish-brown compound
VICTORIA PURE BLUE

A solution used to visualize fingerprints on adhesive surface such as
paper tapes, packaging tapes, etc…
GAS METHOD
IODINE FUMING
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Appropriate Surface:
o porous and non-porous such as paper, index cards,
magazines, and cardboard.
Theory:
o Sweat and oil will absorb iodine vapors
CYANOACRYLATE (SUPERGLUE) FUMING

It is used on a variety of materials not only to visualize latent prints, but
also to semi-permanently affix them to the surface.
OPTICAL METHODS
ALTERNATE LIGHT SOURCES (ALS)

Forensic light source
o Fluorescence (immediate emission)
o Phosphoresence (long-lived)
LASER

Reflected Ultraviolet Imaging System (RUVIS)

GUIDE TO SURFACES AND TREATMENT METHODS

SMOOTH, NON-POROUS
Glass, hard plastic moldings (bare metals are not included) and surfaces treated
with paint or varnish.
TREATMENT
Powders, Iodine, Small Particle Reagent (SPR) and Cyanoacrylate/fluorescent
dyes.

ROUGH, NON-POROUS
Rough, textured surfaces and grained plastic moldings.
TREATMENT
Small Particle Reagent (SPR) or Cyanoacrylate/ fluorescent dyes. Powders are
usually unsuitable on these surfaces.

PAPER AND CARDBOARD
Paper and cardboard (including plaster board) that have not been waxed or
plastic coated.
TREATMENT
Iodine, Ninhydrin, DFO, Silver Nitrate or physical developer. (Note: powders are
generally insensitive to older fingerprints.)

PLASTIC PACKAGING MATERIAL
Polyethylene, polypropylene, acetate and laminated paper surfaces.
TREATMENT
Iodine, Small Particle Reagent (SPR), Cyanoacrylate/fluorescent dyes and
powders. Cyanoacrylate is especially useful on Styrofoam.

SOFT VINYL (PVC), RUBBER and LEATHER
Simulated leather and cling film.
TREATMENT
Iodine, SPR, Cyanoacrylate and powders.

METAL (UNTREATED)
Untreated, bare metal surfaces— not metal surfaces that have been painted or
lacquered.
TREATMENT
SPR, powders, Cyanoacrylate/fluorescent dyes and powders.

UNFINISHED WOOD
Unfinished wood surfaces that have not been painted or treated.
TREATMENT
Ninhydrin. Use powders on smooth wood and Silver Nitrate or physical developer
on light woods.

WAX AND WAXED SURFACES
Items made of wax (such as candles) and wax-coated paper, cardboard and
wood surfaces.
TREATMENT
Nonmetallic powders and Cyanoacrylate/fluorescent dyes.

ADHESIVE-COATED SURFACES
Tapes and similar surfaces that are not likely to dissolve in water.
TREATMENT -Adhesive side powders.
Forensic 7 - March 18, 2021 Zoom
Gathering, Preservation, and Continuity of Evidence
Definition of terms:
1. Evidence - is the means sanctioned by the rules of court in ascertaining in judicial
proceedings the truth respecting a matter of fact.
1. Uses five senses
2. Existing
3. Physical evidence, not testimonial or documentary (although covered)
4. Collection of evidence serves as proof
5. Degree of proof
1. Proof beyond reasonable doubt - Criminal cases
2. Preponderance of evidence - Civil cases
What happens if there is a doubt in evidence?
 When there is a doubt, in any piece of evidence, it always is in favor of the
accused.
 Not accepted - inadmissible in court
Forensic science under Special Crime Investigation - Special Investigative Techniques
Application of criminalistics
2.
DNA (Deoxyribonucleic Acid) - is the genetic code of the chromosome contained inside
the nucleus of a human cell, responsible for the physical difference between individuals, that no
two people have the same DNA (except identical twins).
a.
Biological evidence
b.
Single egg cell fertilized by two sperms (Identical)
c.
Two egg cells fertilized by two sperms (Fraternal)
d.
The result is conclusive already
e.
It is prima facie in nature
f.
Usually used in sexual assault
i.
Treat the body of the victim as the crime scene itself
ii.
Do not allow the victim to change clothes, wash, to take a bath
iii.
The victim should undergo processing first
1. Vaginal/anal swab
iv.
Aggravating circumstance of rape
1. When rape is done in an unnatural way
2. Normal position: Man-on-top
1. Found out through position of injury in vaginal orifice
3. Statutory rape
v.
Provisions of RA 8353
vi.
Can a man rape a woman? Yes.
vii.
Can a man rape another man? Yes.
viii.
Can a woman rape a man? Yes.
1. Somehow impossible for rape. Instead, acts of lasciviousness
ix.
Sexual harassment happens when a person in higher authority harasses a person
inferior to them.
x.
Unjust vexation
xi.
Oral, vaginal, anal - Involved in rape
3.
Trace Evidence - are physical evidence that can establish the physical contact of the
suspect with the victim to prove his physical presence in the crime scene, such as glass
fragments, paints, tool marks, fingerprints, footwear marks, tire marks, arson, and explosive
evidence
a.
Limited to physical evidence
b.
Associative evidence - property of suspect find in the crime scene
c.
Affidavit of loss needed when you lose something (ID etc)
d.
Prove your innocence
4.
Latent Prints - Those markings usually rather indistinct, left by oily matters or
perspiration exuded from the fingertips upon any substance, which the fingers may have
touched
Must undergo processing
Inventory of evidence
Impeachment of witness - incompetent
What are the implications of proper evidence processing to Forensic
examination?
1. Proper handling of physical evidence is necessary to obtain the maximum possible
information upon which scientific examination shall be based and to prevent its exclusion
as evidence in a competent court.
1. Evidence is competent when it is not excluded in the Rules of Court
2. Test of inadmissibility of evidence:
1. Competent
1. The doctrine of the poisonous tree
2. Exclusionary rule - when the evidence was gathered as a result of
a violation of rights of the accused
2. Relevant
c.
Miranda vs. Arizona - Miranda Doctrine
d.
The purpose of this is to ensure the maximum possible information derived from
evidence
2.
Specimens that truly represent the material evidence found at the crime scene, and
remain unaltered, unspoiled, or otherwise unchanged, in the course of handling, would provide
more and better scientific information upon examination.
a.
If evidence made visible, photograph the same
b.
Preserve the evidence found at the crime scene until the time it reaches the court
c.
If evidence is a gun, you cannot touch it
i.
4 basic rules of gun handling:
1. Always point the muzzle in a safe direction.
ii.
2. Always treat every gun as if it were loaded.
3. Always be sure of your target and beyond.
4. Always keep your finger off the trigger until you are ready to shoot.
Featherlight - small movement in triggers cause the gun to shoot
When is the collection of evidence accomplished?
Collection of evidence is accomplished after the search is completed, the rough sketch finished
and photographs were taken.
1. First responder - civilians
2. Police first responder
1. An initial cordon of the crime scene
2. Note-taking
3. Persons detained for purposes of questioning
3. The investigator on the case will arrive
1. Police first responder transfer all documents to the investigator
2. Investigator will assess the crime scene
4. If heinous or sensation crime, crime lab technicians required. If not, investigators
process the crime scene, no need for the crime lab.
5. When the crime lab team arrive, there is initial walk-through
6. Briefing will happen next
7. Then crime scene search happen based on pre-established facts base on briefing
1. Crime scene search for vehicles - Zone method
2. Point search - used by inexperienced investigators
1. Discouraged to use
Collecting pieces of evidence
.
Chain of custody
a.
Logging, label, packaging
b.
Preservation
Final walk-through
.
There might be pieces of evidence that might be left or unidentified during the initial
walk-through and recovery process
Crime scene
.
Public space - release to local authorities
a.
Public property - release to the owners
b.
Chief of police will decide if crime scene released or not
What are the principles to be observed in handling all types of physical
evidence?
1. The collected evidence should reach the laboratory as much as possible in the same
condition as when it was found.
2. The quantity of collected specimens shall be adequate for purpose of forensic
examination. Even with the best available equipment, good test results cannot be
obtained from insufficient specimens.
1. Blood is the most common evidence
1. When blood is on floor and dried, use distilled water and scrape it off.
Rule in marking evidence:
Do not mark the item with evidentiary value.
3.
Submit a known or standard specimen for comparison purposes.
a.
Questioned - from the crime scene
b.
Known - standard specimen
c.
Compare questioned to known.
d.
In fingerprints, known will be from the suspect. Or from document records if there are no
suspects.
i.
AFIS - 10 nearest match, manually comparing
1. Criminal Prints
2. Civilian Prints
3. Unknown Prints - from crime scenes that are identified
e.
Kibitzers
4.
Keep each specimen separate from the others. Wrap and seal in individual packages
when necessary.
a.
Different specimen, different packaging
b.
All evidence can have marking or tagging
i.
Tagging - information is not put directly on evidence
1. Initials
ii.
Choice of the container is of paramount importance
1. Biological evidence
1. If liquid, put in a vial
2. Other biological evidence, put in paper container
5.
6.
7.
a.
Mark or label each piece of evidence for positive identification.
The chain of custody of evidence must be maintained.
Any break in this chain of custody may make the material inadmissible in Court.
Exclusionary Rule
Latent Prints and Standard Fingerprints
a.
Latent prints - on paper, glass, metal, or other smooth surfaced objects
b.
When articles containing latent prints must be picked up, touch as little as possible and
then only in areas least likely to contain identifiable latent prints such as rough surfaces.
c.
While gloves or handkerchiefs may be used to pick-up exhibits, any unnecessary contact
should be avoided. Although using a cloth to pick-up exhibits prevents leaving additional prints
on the article, the cloth will frequently wipe off any print originally present unless they are
immediately taken.
Use PPE in collecting latent prints.
d. Lifted prints are to be marked at the back portions of the lifting tapes indicates the date
and time of collection and place where the print was lifted, case number, name and
signature of collecting officer, and signature of at least 2 witnesses.
e.
Standard fingerprints should be taken with utmost care. Complete detail of the ridges
should be clearly and neatly recorded for comparative examinations. Stamp pad and other
ordinary ink should not be used for fingerprint recording.
f.
Containers of the specimen may conceal fingerprints. So dusting them is necessary.
Send any prints that may be found to the laboratory.
Checklist for submitting evidence to the laboratory
Before submitting the evidence to the laboratory, the following checklist should be conducted:
ALL ANSWERS ARE YES
1. Did I collect all the available evidence in this case?
2. Did I collect a sufficient amount of each type?
3. Was I careful not to alter the material in handling and in preparing it from transmittal to
the laboratory?
CASES/PROBLEMS:
1. Scene 1 - busy investigator, causing confusion
2. Scene 2 - crime lab officer is distracted, busy
3. Scene 3 - no turn-over receipt, no chain of custody form
Fingerprint System
1. The Ten Fingerprint System - whose basic material is the 10 fingerprints of the suspect
whose purpose is to confirm the identity and criminal history of an arrested suspect
1. This is where standard fingerprint comes from
2. Single Fingerprint System - whose basic material is the fingerprint collected from the
suspect individually
Fingerprint Identification
Purpose: To establish the identity of non-identity of two sets of inked fingerprints
 Reflected in the findings
 Prove question and known are similar.
o Questioned is found to be similar to the left index finger of the suspect.
 Conclusion: It came from one and the same person.
o Basis for investigator to assume said suspect was at the crime scene.
o Positive identification of suspect.
o Not to prove innocence or guilt of person.
What points are identified?
Ridge characteristics
Characteristics are distinguished attributes or elements used in fingerprints to make an
identification. These are also known as ridge detail, points of identification, ridge characteristics
or identifying characteristics.
Ex: Ending ridges, bifurcations, dots, enclosures, short ridges

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Identify relative position
Perform ridge count
Juxtapose when trying to conduct comparison - same plane, the same level of
magnification
ACEV method
o Analysis
 Comparison of general characteristics
 Do not compare whorl from loop
o Comparison
 Look for individual characteristics
o Evaluation
 Findings
 Similarity, differences
o Verification
 To avoid mistakes
 Verification by another fingerprint technician
In the Philippines, we use 12 point comparison as standard unless there are partial
prints
It’s better when you find rare characteristics
How are fingerprints compared?
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Fingerprints are compared by noting the ridge characteristics in two fingerprint
impressions to determine whether or not the match. An identification is established when
a number of these characteristics occupy the same relative position in 2 fingerprint
impressions.
o In conduct of comparison, mark the laten prints first.
When making comparison, the first observation should be, are the fingerprints of the
same type? (Analysis)
If they are of the same type, proceed with the examination of the minutiae. If they are of
different type, no further comparison be made.
In looking for characteristics, begin first with those that capture your attention when first
looking at the impression.
o The first observed is core
o When partial print, the topmost portion is where you start
Count the ridges from the first point to the next point and continue the process until you
have determined that the two prints are the same.
o Do it in a clockwise manner/pattern.
When can we say there is a match?
1.
2.
3.
4.
Likeness of general pattern types
Qualitative likeness of the friction ridge characteristics (General characteristics)
Quantitative likeness of the friction ridge characteristics (Minutiae)
Likeness of location of the friction ridge characteristics
How many points of identification are sufficient to establish an
identification?
A.
B.
No standard number required.
Left to each individual examiner
Deciding factors:
1. Clarity of impression
2. Uniqueness of formation
3. Fingerprint examiners experience and ability
98% of the time partial prints are recovered.
Preparing Fingerprint Chart For Court Presentation
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It is not only necessary that the fingerprints expert’s testimony is capable and be able to
put up a good line of argument in favor of the fingerprint. Method of identification, should
he be called to testify on the witness stand and to substantiate his opinion or argument.
The fingerprint technician who conducted the examination will be called to testify on the
witness stand to testify on matters of the examination he conducted.
When qualified he will be considered as an expert witness.
For a good expert witness:
Training
Education
Experience
The court will qualify you as an expert witness.
Who is an expert witness?




A person who, through experience, training and education, has complete knowledge and
skill in the science of fingerprints and if called upon by courts, to testify, can externalize
that knowledge and skill in a forceful yet convincing and intelligent manner.
The law is very specific about who an expert is. We can see that even though a person
may never have appeared in court, he may very well possess the requisite qualification
for an expert witness.
It makes little difference even if a person never testified in court.
It should be borne in mind that it is the court that declares a person, an expert.
Preparing a Chart




Use cardboard (1/32”)
Enlarge the corresponding known prints of the suspect from the Fingerprint Card.
(8”x10”)
Any discrepancy made in making a ridge characteristics on the original or small print will
be enhanced in the enlargement.
When enlarging a photograph, leave at least 2 inches of margin in the sides for labelling
the point of similarities.
Suggested Procedures:

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Drawn an oval with pencil around the print having at least one inch margin
The point of the oval should be nearly equidistant from the margin of the point as
possible.
Mark with pencil and extend so as to touch the line forming the oval all round the print.
Always mark off the latent print first.
Number the ridge characteristics the same on both prints (latent and standard)
Mark off and number only those minutiae that appears on both prints
Do no attempt to mark the ridge details on the natural size
When ruling the projection line which points out the ridge details, be sure that none of
them cross each other
Do not draw the ink lines so heavily that they will hide the ridge characteristics
Mark the core as number 1 if it is shown in the latent print
Number each ridge characteristics consecutively in a clockwise direction around the print
The two marked points (latent and standard) and table of explanation should be
mounted on a large sheet of paper or chart so as to be in the best and most available
form for explanation.
12 points of similarities is enough to secure conviction. But if the situation warrants,
identify as many as you can.