Forensic Science
The application of science to the
criminal and civil laws that are enforced
by police agencies in the criminal justice
system.
Introduction
Key Terms:
-Algor Mortis
-Autopsy
-Expert Witness
-Liver Mortis
-Locard’s exchange principle
-Rigor mortis
History & Development of Forensic
Science
Today, many people believe that Sir Arthur Conan Doyle
had considerable influence on popularizing scientific
crime detection methods through his fictional character
Sherlock Holmes.
First Sherlock Holmes novel,” A Study in Scarlet,” was
published in 1887.
Sherlock Holmes first applied the principles of :
-Serology
--fingerprinting
--firearms identification
-- questioned document examination
Who’s Who in Forensic Science
The following people have made major contributions to Forensic
Science.
History of Forensic Science
1814: Mathieu Orfila
(B:1787-D:1853)
-”Father of Forensic Toxicology”
-wrote the first scientific paper on the detection of poisons.
- Published articles on the classification of poisons and the detection of poisons
in bodily fluids, tissues, and organs (toxicology).
1879: Alphonse Bertillon
(B:1853-D: 1914)
- First scientific system of personal identification (ANTHROPOMETRY- systematic
system of taking a series of body measurements as a means of distinguishing one
individual from another.)
-Replaced by fingerprinting in early 1900’s, after a case showed that two people
had the same measurements.
1887: Sir Arthur Conan Doyle
- Publishes his first Sherlock Holmes novel, A Study in Scarlet. The
exploits of the main character in his first novel results in a demand for
the use of science in more police work.
1892: Francis Galton ( 1822-1911)
-First definitive study of fingerprints and developed a method for classifying
them.
-In 1892, he published a book called Fingerprints.
-Explains many different characteristics of fingerprints and how they combine
to form a unique print for each person.
1893: Hans Gross ( 1847-1915)
-Wrote the first treatise describing the application of scientific discipline to the
field of criminal investigation in 1983.
-Published the book Criminal Investigation.
-Considered by many to be the first Criminologist.
1898: Paul Jeserich
- Developed Forensic Chemistry.
1901: Karl Landsteiner
-Discovered the ABO Blood Group
1908: The U.S. Bureau of Investigation ( BOI) is formed
with 34 agents.
1910: Albert S. Osborn ( 1858-1946)
-Developed the fundamental principles of document examination
-Author of “Questioned Documents,” in 1910- explains the scientific investigation of
a document of uncertain origin such as, counterfeiting, alteration, obscuring, and
obliteration of written instruments.
1910:Edmond Locard ( 1877-1966)
-Demonstrated how the principles enunciated by Gross could be incorporated within a
workable crime laboratory.
-Established Locard’s Exchange Principle.
-Established a Crime Laboratory in the police department in Lyon, France.
-“ Father of Forensic Science”
1915: Leone Lattes ( 1887-1954)
-Took Karl Landsteiner’s work with ABO Blood Groups and devised a
relatively simple procedure for determining the blood group of a dried
blood stains.
1924: The first Crime Laboratory in the United States is
set up as part of the Los Angeles Police Department.
1925: Bureau of Forensic Ballistics
-Established in New York by C.E. Waite, Calvin Goddard, Phillip Gravelle, and John
Fisher.
1929: Calvin Goddard ( 1891-1955)
-U.S Army Colonel: refined the techniques for weapon & bullet analysis
using a comparison microscope.
-Matches the bullets from the St. Valentine’s Day Massacre to the
weapons from which they were fired.
-“ Father of Firearms Identification”
1932: BOI establishes a forensic crime laboratory.
1935: BOI changes name to the FBI
Federal Bureau of Investigation
Walter C. McCrone ( 1916-2002)
-Used microscopy, often in conjuncture with other analytical methodologies to
examine evidence in thousands of criminal and civil cases.
Locard’s Exchange Principle
$
$
“ Every contact leaves a trace”
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Locard’s Famous Principle
Wherever he steps, whatever he touches, whatever
he leaves, even unconsciously, will serve as a silent
witness against him. Not only his fingerprints or his
footprints, but his hair, the fibers from his clothes,
the glass he breaks, the tool mark he leaves, the
paint he scratches, the blood or semen he deposits
or collects. All of these and more, bear mute witness
against him. This is evidence that does not forget. It
is not confused by the excitement of the moment. It
is not absent because human witnesses are. It is
factual evidence. Physical evidence cannot be wrong,
it cannot perjure itself, it cannot be wholly absent.
Only its interpretation can err. Only human failure to
find it, study and understand it, can diminish its
value.
Illustration of Locard’s Exchange
Principle
• A motorist is driving a 2002 Suzuki XL-7 down
a country road at night during a rainstorm. He
picks up a hitchhiker, stabs him to death with
a knife, and drives the sport utility vehicle (
SUV) into the woods to dispose of the body. A
few days later the body is found in the woods.
How can the police investigating this crime
use locard’s exchange principle?
Role of a Forensic Scientist
• As opposed to what is on television, the role of a
forensic scientist is not to run around searching
for the “bad guy.”
• Role is to analyze physical evidence.
• In the past, forensic scientist’s had college degree
in biology, chemistry, or physics. Additionally,
with experience in lab work or an apprenticeship.
• Now forensic scientist’s graduate from 4 year
universities with degrees in forensic science.
Role of a Forensic Scientist
• Evidence brought to a crime lab Forensic
Scientist analyzes it and gives conclusions to
the investigator.
• Identification, comparison, probability,
reliability of the results.
• Must also testify in court
• Can also be called to testify years later so
forensic scientists must keep good notes.
Role of a Forensic Scientist
• “ Expert” – person with special knowledge,
skill, experience, training and or education
that goes beyond the experience of ordinary
members of the public.
• Can give opinion.
• Also Forensic scientist can often be asked to
train police officers in a specific area.
– Drug hiding capabilities.
Specialized Forensic Science Carreers
• Some Forensic Scientist’s obtain advanced
degrees in medicine, toxicology, odontology,
pathology, psychiatry, engineering,
entomology, and anthropology.
Coroner
• Latin word meaning, “ from the crown.”
• Official, appointed by the king, whose job was
determine the cause of a sudden or unexpected
death.
• Replaced by the Medical Examiner System in
1915.
– A physician who is authorized by state statute to
investigate sudden, unexpected, violent, post of this
investigation is to detect the cause and manner of
death.
Forensic Pathologist
• Physician with specialized training in determining
the cause of death and in forensic science.
• Aid in providing important information uncovered
during the examination of the body. ( Time of
Death)
• Time of Death can be determined using several
methods and is based on many variables.
Because of this reason, a range of time is
normally given.
• The estimate of how long a person has been dead
is called the Postmortem Interval ( PMI)
Forensic Pathologist
• Algor Mortis- the process by which the body cools
after death as a result of the loss of heat to the
surroundings.
• Nomograph- diagram that allows a complicated
mathematical relationship to be solved simply with a
ruler.
• For example: a nomograph can be used to estimate the
time of death based on the deep rectal temperature of
the body, surrounding air temperature, body weight,
and various other correction factors such as presence
of clothing and submersion in water.
Forensic Pathologist
• Liver Mortis-settling of blood at the lowest point
after death.
– Since the heart is no longer pumping blood, gravity
causes blood to pool at the lowest point of the body.
– Turns a purplish blue.
– Process begins as soon as 30 minutes but doesn’t
become permanent until 8 hours after death.
– Can be used to determine if the body was moved after
death, or get some idea about the time of death.
Forensic Pathologist
• Liver Mortis- Stiffening of the muscles of the
body.
– Muscles relax at first and then begin to contractchemical reactions.
– 2 hours after death, head first and then moves to
the extremities.
– Complete after 6 hours and begins to leave the
body after 24 hours.
– 40 hours they are completely gone.
Forensic Pathologist
• Autopsy- a surgical procedure that allows a
specially trained medical doctor to help
determine the previous health of the deceased
and the cause of death.
• Latin- ‘ seeing with your own eyes’
• Pathologist, with help of a diener, performs the
autopsy.
• “Hie locus est ubi mors gaudet succurrere vitae.”
• This is the place where death rejoices to teach
those who live.
Autopsies
• Gross examination of the exterior of the body
and the sheets or bags used to cover and
transport the body.
• Records are made of the - height, weight,
name, and visible characteristics.
• Samples of blood, urine, hair and oral swabs
are taken. Scapings from under the nails. Body
is x-rayed.
The Process
Autopsy Tools
External Examination
Steps of an external examination.
1. Photographed.
2. Physical evidence collected off body.
3. Samples of hair, nails, etc. are collected.
4. Undressed, examined for wounds.
1. Lacerations, abrasions, bruises.
5. Measured, weighed, cleaned
1. Including all organs.
Internal Examination
•
1.
Steps of an internal examination.
Incisions
–
–
–
•
A “Y” shaped cut from behind each ear and running down the
neck, meeting at the breastbone, continuing towards the
groin. Most often used in cases of suspected strangulation.
A “T” shaped cut from each shoulder ,meeting at the
breastbone, continuing towards the groin. Used to create a
better looking finished product as this cut is not often seen.
Single vertical cut from throat to groin.
All cut are deviating towards the left.
Internal Examination (cont’d)
2. Cuts
1. The chest cavity is cut open using shears.
2. The ribs are sawed away, letting them be lifted off the
body, exposing the heart and lungs.
3. Removal
1. En masse technique of Letulle – All organs removed at
once.
2. En bloc method of Ghon – organs divided into four
groups and removed in sections.
4. All removed organs are now weighed and
examined for unusual markings or signs.
Forensic Toxicologist
• Studies toxic substances.
• A person, usually with an advanced degree,
who detects the presence of poisons or drugs
in bodily fluids, tissues, and organs.
• High performance liquid chromatographs, gas
chromatographs, and mass spectrometers
which can detect extremely minute quantities
of toxic or illegal substances in the human
body.
Odontologist
Forensic dentist who applies dentistry to
police investigations.
• Body that has been severely burned or
disfigured, the odontologist can still make a
positive identification through dental records.
• 9/11, Oklahoma City Bombing, Train Accidents
…mass casualties.
• Bite marks as well.
Forensic Psychiatrist
• Medical doctor who specializes in the
application of psychiatry to law.
• Can be asked to develop a profile of a suspect
based on available evidence.
• Testify whether or not the suspect is
responsible for their actions.
Forensic Engineer
• Applies engineering principles to law.
• Often called into cases when there is a
structural failure such as a bridge or building
collapse.
• Analyze the structure and determine the
cause of a failure
• Complicated accident scenes.
Forensic Entomologist
• Applies the study of insects to law.
• Blowfly- lays eggs on dead tissues- attracted
to the chemicals given off by decomposing
flesh- begin laying eggs minutes after deatheggs found in nose, ears, and mouth.
• Lifecycle in Textbook.
Forensic Anthropologist
• Performs specialized examination of human
skeletal remains or badly decomposed bodies
for the purpose of identification.
• Asked to help determine the cause of death,
sex, age, post mortem interval, and race.
• Murder or ancient burial site.
• Reconstruct facial characteristics of the skull
to aid in the identification process.