3. HISTORY
•The first systematic attempt at personal identification
was devised by a French police expert, Alphonse
Bertillion.
•The Bertillion system relied on a detailed description
of the subject, combined with full length and profile
photographs and a system of precise body
measurements called anthropometry.
•In 1892 Francis Galton published his classic textbook
Finger Prints.
4. Fingerprinting
•At Galton’s insistence, the British government adopted
fingerprinting as a supplement to the Bertillion system.
•The next step was the creation of classification systems
capable of filing many thousands of prints in a logical and
searchable sequence.
•Dr Juan Vucetich devised a classification system still used in
most Spanish-speaking countries, while Sir Edward Henry
devised another classification system used in most English-
speaking countries.
5. Fingerprinting
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•In 1903, when the Bertillion system could not distinguish
between two men (one Will West and the other William
West), it was fingerprinting that clearly distinguished
them.
•After the Will West incident, the use of fingerprinting by
the New York City Civil Service Commission in 1901, and
the training of American police by Scotland Yard
representatives at the 1904 World’s Fair, fingerprinting
began to be used in earnest in all major U.S. cities.
6. “Fingerprints found at crime scenes
lead to more suspects and generate
more evidence in court than all other
forensic techniques combined.”
Interpol European Expert Group on Fingerprint Identification (IEEFG) Methods for Fingerprint
Identification Part 1 (2004
7. •Friction ridges on hands are known for
thousands of years
•First suggested by Dr. Henry Flaud in 1880
•The use of chemical compounds for the visualization of
latent prints dates back only about 150 years
•Most commonly used technique for identification of
criminal.
9. 9
Patent Prints
Patent prints occur when a substance such as blood, ink,
paint, dirt, or grease on the fingers of the perpetrator of a
crime leaves behind a readily visible print.
10. 10
Plastic Prints
Plastic prints have a three-dimensional quality and occur
when the perpetrator impresses a print into a soft
substance such as wax, putty, caulk, soap, cold butter or
even dust.
11. 11
Latent Prints
Latent fingerprints are those that are “hidden” and are not visible to the naked
eye. These prints consist only of the natural secretions of human skin and require
treatment to cause them to become visible.
Most secretions come from three glands:
Eccrine--largely water with both inorganic (ammonia,
chlorides, metal ions, phosphates) and organic
compounds (amino acids, lactic acids, urea, sugars)
Apocrine--secrete cytoplasm and nuclear materials
Sebaceous --secrete fatty or greasy substances.
12. 12
Lifting Latent Prints
Here’s where the chemistry comes in……..
Developing a print requires chemicals that react with secretions that cause the
print to stand out against its background. It may be necessary to attempt more
than one technique, done in a particular order so as not to destroy the print.
Powders--adhere to both water and fatty deposits.
Choose a color to contrast the background.
13. Lifting Latent Prints
Iodine-- fumes react with oils and fats to produce a
temporary yellow brown reaction.
Ninhydrin-- reacts with amino acids to produce a purple
reaction.
Silver nitrate-- react with chlorides to form silver chloride,
a material which turns gray when exposed to light.
Cyanoacrylate--”super glue” fumes react with water and
other fingerprint constituents to form a hard, whitish
deposit.
In modern labs and criminal investigations, lasers and
alternative light sources are used to view latent fingerprints.
It was first used by the FBI in 1978. Since lasers can damage
the retina of the eye, special precautions must be taken and
a filter used.
14. • Visible print by unaided eye.
• Example: A good example of a patent print
would be a greasy impression left on a window.
• Also in blood, paint, ink, mud or dust
• These are formed when the raised friction ridges are
physically pushed into the substrate, creating a mold of the
friction skin ridge Clay, soft wax, melted
heavy grease, and paint
plastic,
15. •Good source of imaging for
patent prints
•Plastic impressions are usually
photographed under oblique
lighting that enhances the contrast
of the ridges and furrows.
•These prints may also be
preserved with silicone-type
casting materials.
16. •The word latent means hidden or unseen.
•Latent prints are undetectable until brought out with a physical
or chemical process designed to enhance latent print residue.
•Affected by age, gender, stimuli, occupation, disease, and any
substances the subject may have touched prior to deposition.
•After deposition: surface area, surface curvature/shape,
•surface temperature, humidity, time since they were placed and
temperature.
17. • Help in understanding working of chemicals and
developing new reagents.
• A latent print residue is mixture of secretion from glands.
• 2 major glands in dermis sebaceous glands and
sudoriferous glands (eccrine and apocrine).
• The print is 99% water and rest is trace amount of amino
acids, lipids urea, lactic acid, creatinine, glucose and
drugs.
• 250 ng of amino acid per fingerprint.
They remain there after water evaporates.
18. FINGERPRINT PRINCIPLES
•Fingerprints are a reproduction of friction skin ridges found
on the palm side of the fingers and thumbs.
•The basic principles underlying the use of fingerprints in
criminal investigations are that:
1. A fingerprint is an individual characteristic because no
two fingers have yet been found to possess identical
ridge characteristics
19. FINGERPRINT PRINCIPLES
2. A fingerprint will remain unchanged during an
individual’s lifetime; and
3. Fingerprints have general ridge patterns that permit
them to be systematically classified.
20. PRINCIPLE ONE
•Mathematically, the probability for the existence of two identical
fingerprint patterns in the world’s population is extremely small.
•Besides theoretical calculations, of the millions upon millions of
individuals who have had their prints classified, no two
fingerprints have been found to be identical.
21. PRINCIPLE ONE
•The individuality of a fingerprint is not determined by its general
shape or pattern, but by the careful study of its ridge
characteristics, known as minutiae.
•It is the identity, number, and relative location of these minutiae
that imparts individuality to a fingerprint.
•There are as many as 150 minutiae on the average finger.
22. Ridge Characteristics
Minutiae—characteristics of ridge patterns
• Ridge ending
• Island or short ridge
• Bridge
• Eye or enclosure
• Delta
• Bifurcation or fork
• Dot
• Spur
• Double bifurcation
• Trifurcation
Kendall/Hunt Publishing Company
24. 24
In Court
Courts require different amounts of matching points of
minutia
• UK requires 16 points
• Australia requires 12 points
• FBI requires 12 points
• U.S. courts require 6-8 points
25. 2
5
Arch
An arch has friction
ridges that enter on one
side of the finger and
cross to the other side
while rising upward in
the middle. They do
NOT have type lines,
deltas, or cores.
Types
Plain
Tented
26. 26
Loop
A loop must have one or more
ridges entering and exiting
from the same side it began.
Loops must have one delta.
Types
Radial--opens toward the
thumb
Ulnar--opens toward the
“pinky” (little finger)
Which type of loop is this, if on
the right hand? Left hand?
27. 27
Whorl
A plain or central pocket whorl
have at least one ridge that
makes a complete circuit. A
double loop is made of two
loops and an accidental is not
covered by other categories.
Types
Plain
Central Pocket
Double Loop
Accidental
28. PRINCIPLE ONE
•After a three year study, it was determined that “no valid basis
exists for requiring a predetermined minimum number of friction
ridge characters which must be present in two impressions in
order to establish positive identification.”
•In a judicial proceeding, an expert must demonstrate a point-by-
point comparison in order to prove the identity of an individual.
30. PRINCIPLE TWO
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•The dermal papillae is the layer of cells between the
epidermis and dermis, that is responsible for determining
the form and pattern of the ridges on the surface of the
skin.
•Once the dermal papillae develop in the human fetus, the
ridge patterns will remain unchanged throughout life
except to enlarge during growth.
31. PRINCIPLE TWO
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•Each skin ridge is populated with pores leading to sweat
glands from which perspiration is deposited on the skin.
•Once the finger touches a surface, perspiration, along
with oils that may have been picked up by touching the
hairy portions of the body, is transferred onto that surface,
leaving the finger’s ridge pattern (a fingerprint).
32. PRINCIPLE THREE
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•All fingerprints are divided into three classes on the basis
of their general pattern: loops, arches, and whorls (L.A.W.).
•A loop must have one or more ridges entering from one
side of the print, recurving, and exiting from the same side.
•If the loop opens toward the little finger, it is called an
ulnar loop.
•If the loop opens toward the thumb, it is called a radial
loop.
33. PRINCIPLE THREE
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•All loops must have one delta, which is the ridge point
at or directly in front of the point where two ridge lines
(type lines) diverge.
34. PRINCIPLE THREE
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Whorls are divided into four groups: plain, central pocket
loop, double loop, and accidental.
All whorl patterns have type lines and a minimum of two
deltas.
35. PRINCIPLE THREE
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•A plain whorl and a central pocket loop have at least one
ridge that makes a complete circuit.
•The double loop is made up of two loops combined into
one fingerprint.
•An accidental either contains two or more patterns, or is
a pattern not covered by the other categories.
36. PRINCIPLE THREE
•Arches, the least common of the three general patterns,
are divided into two distinct groups: plain arches and
tented arches.
•The plain arch is formed by ridges entering from one side
of the print, rising and falling, and exiting on the opposite
side (like a wave).
•The tented arch is similar to the plain arch except that
instead of rising smoothly at the center, there is a sharp
upthrust or spike, or the ridges meet at an angle that is less
than 90 degrees.
38. PRIMARY CLASSIFICATION
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•Fingerprint classification systems are based on
knowledge of fingerprint pattern classes.
• First, fingers are paired up, placing one finger in the
numerator of a fraction and the other in the denominator.
•The presence or absence of the whorl pattern is the
basis for the determination of the primary classification.
39. PRIMARY CLASSIFICATION
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•If a whorl pattern is found on any finger of the first pair,
it is assigned a value of 16; on the second pair, an 8; on
the third pair, a 4; on the second pair, a 2; and on the last
pair, a 1.
•Any finger having a loop or arch is assigned a 0.
40. PRIMARY CLASSIFICATION
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•After values for all 10 fingers are obtained, they are
totaled, and a 1 is added to both the numerator and
denominator.
•The fraction thus obtained is the primary classification.
•Approximately 25 percent of the population falls into the
1/1 category; that is, all their fingers have either loops or
arches.
42. Primary Classification, continued
Assign the number of points for each finger that has a whorl and
substitute into the equation:
Kendall/Hunt Publishing
Company
42
right right left left left
index ring thumb middle little + 1
right right right left left
thumb middle little index ring + 1
That number is your primary classification number.
=
43. PRIMARY CLASSIFICATION
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•A fingerprint classification system cannot in itself
unequivocally identify an individual; it will merely
provide the fingerprint examiner with a number of
candidates, all of whom have an indistinguishable set of
prints in the system’s file.
44. AFIS: AUTOMATED FINGERPRINT
IDENTIFICATION SYSTEMS
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•The heart of AFIS technology is the ability of a computer
to scan and digitally encode fingerprints so that they can
be subject to high-speed computer processing.
•AFIS aids in classifying and retrieving fingerprints by
converting the image of a fingerprint into digital minutiae
that contain data showing ridges at their points of
termination (ridge endings) and their branching into two
ridges (bifurcations).
45. AFIS: AUTOMATED FINGERPRINT
IDENTIFICATION SYSTEMS
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•When the search is complete (a computer can make thousands
of comparisons per second), the computer produces a list of file
prints that must be examined by a trained fingerprint expert.
46. LATENT PRINTS
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•Once the finger touches a surface, body perspiration
and/or oils present on the finger ridges are transferred
to that surface, leaving an impression.
•Prints deposited in this manner are invisible to the eye
and are commonly referred to as latent or invisible
fingerprints.
47. VISIBLE PRINTS
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•Visible prints are made when fingers touch a surface after
the ridges have been in contact with a colored material such
as blood, paint, grease, or ink.
Inked
Crystal Violet
Courtesy of C. Fanning
Courtesy of C. Fanning
48. VISIBLE PRINTS
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•Plastic prints are ridge impressions left on a soft material,
such as putty, wax, soap, or dust.
•Locating visible or plastic prints at the crime scene normally
presents little problem to the investigator, because these
prints are usually distinct and visible to the eye.
49. LATENT PRINTS
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•Latent prints deposited on hard and nonabsorbent surfaces
(e.g., glass, mirror, tile, and painted wood) are preferably
developed by the application of a powder; whereas prints on
porous surfaces (e.g., papers, cardboard, and cloth) generally
require treatment with a chemical.
•Examiners use various chemical methods to visualize latent
prints on porous surfaces, such as iodine fuming, ninhydrin, and
Physical Developer.
50. LATENT PRINTS
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•Super Glue® fuming develops latent prints on nonporous
surfaces, such as metals, electrical tape, leather, and plastic
bags.
•Development occurs when fumes from the glue adhere to
the print, usually producing a white latent print.
51. DETECTING PRINTS
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•A devise called the Reflected Ultraviolet Imaging System can
aid in the detecting of latent fingerprints, without chemicals or
powder.
•Once located, the crime scene investigator can develop the
print in the most appropriate fashion.
•Powders, available in a variety of colors, can be applied with a
brush or magnetic wand, and adhere to perspiration and/or body
oils of the print.
52. DETECTING PRINTS
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Iodine fuming involves heating iodine crystals that cause
vapors which combine with latent prints to make them
visible.
Iodine prints are not permanent and will fade, making
it necessary to photograph the prints immediately.
53. DETECTING PRINTS
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•Ninhydrin reacts chemically with trace amounts of amino
acids present in latent prints to produce a purple-blue color.
•Physical Developer is a silver nitrate-based reagent used
to develop prints when other chemical methods are
ineffective.
•Super Glue® is approximately 98 to 99 percent
cyanoacrylate ester, a chemical that actually interacts with
and visualizes a latent fingerprint.
54. DETECTING PRINTS
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•Super Glue fuming can be accomplished by using either a
fuming chamber (for up to six hours) or a handheld wand
that heats a small cartridge containing cyanoacrylate.
•The high sensitivity of fluorescence serves as the
underlying principle of many of the new chemical
techniques used to visualize latent fingerprints.
55. DETECTING PRINTS
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•Fingerprints are treated with chemicals that would induce
fluorescence when exposed to lasers, or high-intensity light
sources (“alternate light sources”) such as quartz halogen, xenon
arc, or indium arc light sources.
•Once the latent print has been visualized, it must be
permanently preserved for future comparison and for possible
use as court evidence.
•A photograph must be taken before any further attempts at
preservation are made.
56. TRANSPORTING PRINTS
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•If the object is small enough to be transported without
destroying the print, it should be preserved in its entirety.
•Prints on large immovable objects that have been
developed with a powder can best be preserved by “lifting”
with a broad adhesive tape.
•Then, the tape is placed on a properly labeled card that
provides a good background contrast with the powder.
57. DIGITAL IMAGING
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•Digital imaging is the process by which a picture is converted
into a digital computer file.
•With the help of digital imaging software, fingerprints, which are
often not in perfect condition, can now be enhanced for the most
accurate and comprehensive analysis.
•An important and useful tool, especially for fingerprint
identification, is the compare function that places two images side
by side and allows the examiner to chart the common features on
both images simultaneously.
