Chapter 6
Fingerprints
By the end of this chapter you will be able to:
o Discuss the history of fingerprinting
o Describe the characteristics of fingerprints and fingerprinting minutiae
o Explain when and how fingerprints form
o Describe how fingerprints can be left on objects
o Identify the basic types of fingerprints
o Describe how criminals attempt to alter their fingerprints
o Determine the reliability of fingerprints as a means of identification
o Describe the Integrated Automated Fingerprint Identification System (IFAIS)
o Explain how fingerprint evidence is collected
o Describe the latest identification technologies
o Determine if a fingerprint matches a fingerprint on record
o Use the process of lifting a latent print
Vocab
o Arch: a fingerprint pattern in which the ridge pattern originates on one side of the print and
leaves from the other side of the print
o Core: a center of a loop or whorl
o Delta: a triangular ridge pattern with ridges that go in different patterns above and below a
triangle
o Fingerprint: an impression left on any surface that consists of patterns made by the ridges on a
finger
o Latent fingerprint: a hidden fingerprint made visible through the use of powders or other
techniques
o Loop; a fingerprint pattern in which the ridge pattern flows inward and returns in the direction
of the origin
o Minutiae: the combination of details in the shapes and positions of ridges in fingerprints that
make each unique; AKA ridge characteristics
o Patent fingerprint: a visible fingerprint that happens when fingers with blood, ink, or some
other substance on them touch a surface and transfer the pattern of the fingerprint onto that
surface
o Plastic fingerprint: a 3D fingerprint made in soft material
o Ridge pattern: the recognizable pattern of the ridges found in the end joints of fingers that
form lines on the surfaces of objects.
o Ten card: a form used to record and preserve a person’s fingerprints
o Whorl: a fingerprint pattern that resembles a bull’s-eye
Historical Development
1. 3rd century B.C. in China—______________ known documents
2. Ancient Babylon (1792-1750 B.C.)—fingerprints pressed into clay tablets marked _____________
3. 1684—Dr. Nehemiah’s paper describes the patterns on human hands, including the presence of
______________
4. 1788—Johann Mayer noted that the arrangement of skin ridges is never ______________ in two
persons
5. 1823—Jan Evangelist Purkyn describes ______________ fingerprint patterns
6. 1856—Sir William Herschel ______________ the collection of fingerprints and noted they were
not ______________ by age
7. 1883—Alphonse Bertillon created a way to identify criminals that were ______________
offenders
• First used in ______________
• First murder solved using fingerprints ______________
8. 1888—Sir Francis Galton and Sir Edmund Richard Henry developed the fingerprint
______________ system still used in the US
9. 1891—Iván (Juan) Vucetich collected all ______________ fingerprint impressions and noted
measurements
10. 1896—Sir Henry, with two colleagues, created a system that ______________ fingerprints into
groups. All ten fingerprints are imprinted on a card (called a ten card) along with other notations
Example of a Ten Card
What Are Fingerprints?
o All ______________, ______________, ______________, and ______________ are covered in
small ridges
o Ridges help us ______________ objects
o Ridges are arranged in connected units called ______________, or ______________, ridges
o Fingers accumulate natural ______________ and ______________
• Composed mostly of ______________, ______________, and ______________
o Fingers leave/create prints on objects we touch
Structure of Skin
Formation of Fingerprints
o Skin consists of:
• Inner layer—______________
• Outer layer—______________
• ______________ layer in between
o Basal layer grows ______________ than the layers above and below it
o Basal layer collapses and ______________ to form intricate shapes
o Fingerprints begin forming near the ______________ week of pregnancy
Characteristics of Fingerprints
o There are 3 general fingerprint distinctions:
ARCH About ____%
WHORL About ____%
LOOP About ____%
o Arches
• Ridges enter from one side and leave from the other with a ______________ in the
center
o Whorls
• Look like ______________ with two deltas (or ______________)
o Loops
• Enter from right or left and exit on the ______________ side
Forensic examiners look for
• Core (the ______________ of a whorl or loop)
• Deltas (______________ regions near a loop)
o Ridge count
• Counting from the ______________ to the ______________ of the delta
• Distinguishes one fingerprint from another
o
o
Basic patterns can be further divided:
• Arch patterns:
 ____% plain
• Pattern does not make an ______________ as it rises in the middle
• Has no characteristics of the ______________ pattern
o
 1% tented
• Does form an ______________ as it rises
• May have characteristics of loop pattern such as ______________
Even twins have ______________ fingerprints
Whorl patterns:
 ____% Plain whorl
• 1+ ridges make ______________ spiral
• ____ deltas
• Line connecting deltas will ______________ or ______________ at least
one ridge in the inner pattern
 ____% central pocket
• 1+ ridges make complete ______________
• ____ deltas
• Line connecting the deltas, ______ ridge from inner pattern will be cut or
touched by the line
 ____% double loop
• ____ separate loop formations
• ____ deltas
 ____% accidental
• ____ or more deltas
• Combination of ______________ of the other patterns not including plain
arch
Fingerprint Minutiae Patterns
o Minutiae
• ______________ characteristics of ridge patterns
• Used to ______________ individual suspect or victim
• Approximately ______ on one full fingerprint
• To identify a person, a ______________ of minutiae must be used
•
Types of Fingerprints
• There are 3 types of prints that investigators look for at crime scenes:
1. Patent fingerprints—______________ prints transferred onto ______________ surfaces
by blood or other liquids
2. Plastic fingerprints—indentations left in ______________ materials such as clay or wax
3. Latent fingerprints—made visible by dusting with ______________ or the use of
______________
Fingerprint Forensic FAQs
o How are latent fingerprints collected?
Can fingerprints be erased?
Only ______________; they will grow back if removed with chemicals
o Is fingerprint identification reliable?
______, but analysts can make mistakes
o Can computers perform matches in seconds?
____, but the FBI’s Integrated Automated Fingerprint Identification System (IAFIS or AFIS) can
provide a match in ____ hours
The Future of Fingerprinting
o New scanning technologies
• Yield ______________ in minute patterns
• Reduce analytical ______________
• Analyze ______________ elements of objects on the skin
o Technologies that recognize patterns in
• ______________
• ______________
• ______________ in your palm
o
Pedro Ramón Velásquez (1892)
On June 29, 1892, in the village of Necochea, Buenos Aires, two children, Ponciano Carballo Rojas, age
six, and his sister Teresa, age four, were found brutally murdered in their home. Their mother,
Francesca, age 27, was found with a superficial knife wound to the throat. The police started an
investigation that affled them. Francesca told police that her neighbor, Pedro Ramon Velasquez, had
committed the crime. Velasquez, a one-time suitor of Francesca’s, did not confess, even after being
tortured. Inspector Commissioner Alvarez went to the crime scene to reexamine it, searching for any
trace of evidence that might have been overlooked. He spotted bloody fingerprints on the doorpost of
the house. Because Francesca had denied touching the bodies of her children, Alvarez believed he had
found an important clue. He took the bloody doorpost and fingerprint samples of Pedro Velasquez
(Figure 6-18) to Juan Vucetich, who in late 1891 had opened the first fingerprint bureau in South
America in Buenos Aires. Vucetich examined the fingerprints and found they did not match. Alvarez
became suspicious of Francesca, who had been so insistent that Velasquez had committed the crime. He
took a sample of her fingerprints and discovered that they matched the bloody prints found on the
doorpost of the house. When Francesca was confronted with the evidence against her, she confessed.
She had murdered her own children, faked an attack on herself, and cast blame on an innocent man,
intending him to die for the crime. Her reasons for the murder and for blaming Velasquez were that he
had interfered in a romance between her and another suitor, and she felt she would be more appealing
to the other man if she did not have children. Francesca Rojas was the first person in the Americas to be
convicted of a crime based on fingerprint evidence.
Stephen Cowans (1997)
On the afternoon of May 30, 1997, Boston police officer Gregory Gallagher was shot with his own gun in
a backyard in Roxbury, Massachusetts. Still carrying the gun, the assailant ran to a nearby residence,
where he received a glass of water as he wiped off the gun. Stephen Cowans was eventually identified as
the shooter. Investigators found a print on the glass used by the individual. The print was matched to
prints of Cowans by two fingerprint examiners with the Boston Police Department. Cowans maintained
his innocence. With the compelling fingerprint evidence, Cowans was convicted of the shooting and
sentenced to 30 to 45 years in the state prison. In 2004, Cowan’s defense team requested DNA testing of
the glass and a baseball cap dropped at the scene of the shooting. Neither DNA sample matched
Cowan’s DNA, although they did match each other. The original verdict was overturned. As Suffolk
County reexamined the fingerprints as it prepared to retry Cowans, the assistant district attorney
discovered “conclusively and unequivocally that . . . the purported match was a mistake.” Cowans was
released from prison after 6. years. As a result, Boston police and the Suffolk County District Attorney’s
office established new guidelines for identification and evidence handling.