Transcript Week 06_Fingerprints

FINGERPRINTS
FINGERPRINTS
• Introduction
– Most widely used of personal identification
techniques
– Involves the study and classification of
fingerprints
– The development of latent prints
– Comparison of known and unknown
fingerprints.
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• Objectives
– Understand the anatomy of skin as it
relates to fingerprints
– Fingerprint classification systems
– Fingerprint characteristics
– Development of latent prints
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• The Anatomy of Skin
• 3 layers
– The Epidermis
– The Dermis
– The Hypodermis
• Each ridge of the
epidermis (outer skin) is
dotted with sweat pores
and is anchored to the
dermis (inner skin).
FINGERPRINTS
• RIDGE arrangement on every finger of every
human being is unique
• Fingerprints serve to reveal an individual's true
identity despite personal denial, assumed names,
or changes in personal appearance resulting from
age, disease, plastic surgery, or accident
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• The Anatomy of Skin
• 3 layers
– The Epidermis: varies in thickness
depending on the body area and contains
no blood vessels
– The Dermis: a thick layer of connective
tissue that contains blood vessels and
provides nutrients and blood to the
epidermis
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• The Anatomy of Skin
The skins appendages or accessory
structures are embedded in the epidermis
and dermis. The accessory structures
include:
– Hair follicles
– Sweat glands
– Sebaceous glands
– Nails
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• The Anatomy of Skin
– The Hypodermis: the subcutaneous tissue
that lies below the dermis, and consists of
connective tissue, fat cells, macrophages,
fibroblasts, blood vessels, nerves and the
base of the accessory glands
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• Functions of the Skin
– Provides the first line of defense against
invasion by microorganisms and foreign
materials
– Inhibits excessive fluid loss
– Important in controlling body temperature
– Sensory functions
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• How Made
– Formed from the RIDGES and GROOVES
on the tips of fingers, toes, and palms,
which are generated from the DERMAL
LAYER of the skin PRIOR TO BIRTH and
are totally unique to that person.
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Alphonse Bertillion
French Police Officer
Devised and
introduced the first
systematic attempt
at personal ID
based on body
types in 1883
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In 1880, Dr. Henry Faulds
began a study of
“skin-furrows” after
noticing the finger
marks on certain
pieces of artifacts.
Suggested that skin ridge
pattern could be
important for the ID of
criminals.
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Francis Galton
• 1892 Book on
Fingerprints
• Naming 3 patterns
– Loop
– Arch
– Whorl
•
•
Demonstrated that
no two are unlike
Fingerprints
remain unchanged
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1893 - Dr. Juan
Vucetich - Argentine
police officer
His classification
system has been
refined over the
years and is still
widely used today in
most Spanishspeaking countries.
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1897, Sir Edward
Richard Henry
The fingerprinting
bureau - founded at
Scotland Yard in
1901
Today, most Englishspeaking countries,
including the US,
use a version of
Henry’s system to
file fingerprints.
FINGERPRINTS
• 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.
FINGERPRINTS
Fingerprint Classification
3 basic principles:
1. Fingerprints are an individual
characteristic
2. They remain unchanged
throughout a person’s lifetime
3. They have general ridge
patterns (friction ridges) that
allow them to be classified
and used in personal ID
LATENT PRINTS
• An important part of
a forensic
investigation is the
identification of the
victim or suspect.
One of the most
useful identification
tools is the
fingerprint pattern.
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Classification of Fingerprints
Arch
Loop
Whorl
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Fingerprints are classified in a three-way
process:
1. By the shapes and contours of individual
patterns
2. By noting the finger positions of the pattern
types
3. By relative size, determined by counting the
ridges in loops and by tracing the ridges in
whorls
FINGERPRINTS
Ridge Patterns
• 3 Basic types
1. Loops – 60%
2. Whorls – 35%
3. Arches – 5%
Loops
Whorls
Arches
Population Distribution of Ridge Patterns
Fingerprint Patterns
22
FINGERPRINTS
In this picture the
technician is
demonstrating
the location of
ridge endings,
bifurcations and
dots.
PRINCIPAL 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.
PRINCIPAL TWO
• 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.
Thus, a fingerprint will remain unchanged during
an individual’s lifetime.
PRINCIPAL TWO
• 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).
PRINCIPAL THREE
• 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.
• 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.
PRINCIPAL THREE
• 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.
• 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.
PRINCIPAL 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.
• Arches do not have type lines, deltas, or cores.
THE LOOP
• The LOOP is a classification of fingerprints
characterized by ridge lines that enter from
one side of the pattern and curve around to
exit from the same side if the pattern.
• A loop MUST have:
– One of more ridges entering from one side
of the print and re-curve and then exit from
the same side.
-Ulnar Loop -Radial Loop
-Delta
-Core
THE WHORL
• The WHORL is a
class that includes
ridge patterns that
are generally rounded
or circular in shape
and have two deltas.
• Divided into 4 groups
–
–
–
–
Plain Whorls
Central Pocket Loop
Double Loop
Accidental
THE ARCH
• The ARCH is a classification of
fingerprints characterized by ridge
lines that enter the print from one side
and flow to the other side.
• Two types:
– Plain
– Tented
• Arches do not have type
lines, deltas, or cores.
Fingerprint Ridge Characteristics
33
Fingerprint ridge characteristics. Courtesy Sirchie Finger Print
Laboratories, Inc., Youngsville, N.C., www.sirchie.com.
34
A fingerprint exhibit illustrating the matching ridge characteristics
between the crime-scene print and an inked impression of one of the
suspect’s fingers. Courtesy New Jersey State Police.
35
Figure 14–5 Loop pattern.
36
Whorl patterns.
37
Arch patterns.
38
PALM PRINTS
LATENT PRINTS
HENRY SYSTEM Converted ridge patterns into letters and
numbers in the form of a fraction
– Too cumbersome for large # of
patterns
– Due to this, and the need to file
millions of fingerprint cards at the
FBI, a modified Henry System was
implemented.
LATENT PRINTS
• The FBI system
– A system based on an applied
classification formula
– Based on a series of modifications
and extensions of the Henry System
PRIMARY CLASSIFICATION
• 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.
• 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.
PRIMARY CLASSIFICATION
• 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 % of the population falls into the 1/1
category; that is, all their fingers have either loops or arches.
• 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.
LATENT PRINTS
• Primary Classification the first classification
method that allowed all
fingerprint cards to be
divided into 1024
groups. It was based on
the presence or
absence of a whorl
pattern.
R. Index (16)
R. Thumb
R. Ring (8)
R. Middle
L. Thumb (4)
R. Little
L. Middle (2)
L. Index
L. Little (1)
L. Ring
LATENT PRINTS
The FBI system
1.
2.
3.
4.
5.
6.
7.
8.
Primary Classification
radial loop
• Can divide all the
fingerprints in the world
ulnar loop
into
1024
groups
double loop
central pocket loop • Not widely used
• http://www.nifs.com.au/
plain arch
FactFiles/Fingerprints/h
tented arch
ow.asp?page=how
plain whorl
accidental
LATENT PRINTS
Major
Fingerprint
Characteristics
• Typelines
• Deltas
• Cores
LATENT PRINTS
Surface Print:
the same
fingerprint as it
would be detected
on a surface.
LATENT PRINTS
Classification of
Loops:
1. Delta
2. Sufficient recurve
3. Ridge count
4. Radial/ulnar loops
Classification of
Arches:
1. Plain arches
2. Tented arches
3. Angular
4. Up thrust
http://155.217.58.58/cgi-bin/atdl.dll/fm/19-20/ch7.htm#s8
http://biometrics.cse.msu.edu/fingerprint.html
Websites show an array of fingerprint patterns.
LATENT PRINTS
Fingerprint Impressions:
Inked Fingerprint Examination
– Fingerprints from the
Living!
Start with clean hands – not
just yours!
LATENT PRINTS
•
•
•
•
Rolled Impressions
Plain Impressions
Palm Prints
Major Case Prints
LATENT PRINTS
Obtaining Impressions from Corpses
Major Case Prints are always obtained from
corpses
• Used to identify or eliminate latent print
evidence
• Identification of the deceased
LATENT PRINTS
“Dusting For Prints”
Latent Fingerprint
Development
Means to develop latent
prints include:
Processing evidence and
other surfaces using
powders, chemicals and
specialized lighting
techniques
LATENT PRINTS
• Friction Ridges
• Latent Prints- Some
impressions are easily
seen (called patent
prints) and others can
only be seen with
specialized techniques
and are called latent
prints.
LATENT PRINTS
Indented Prints prints that are easily
seen embedded in
some type of soft
surface, such as putty,
plaster, sand or candle
wax.
LATENT PRINTS
Techniques of Print
Processing
• At the Crime
Scene
– examine all surfaces
and objects
– photograph and
collect all indented
and visible prints
LATENT PRINTS
The visibility of latent prints depends on
numerous factors:
• The physical condition of the person who left
the print
• The surface of the object
• Lighting angles
• The time since the prints were placed
• Amount of heat to which they have been
exposed
LATENT PRINTS
The amount of time prints remain on an
object is affected by:
– Weather
– Air currents
– Humidity
LATENT PRINTS
Latent print evidence is divided into two
categories:
– Porous
• paper, unfinished wood, cardboard
– Non-porous
• plastic, glass, metal, foil
LATENT PRINTS
• Porous evidence - paper, unfinished wood,
cardboard
– Usually preserved well because print
residue can soak into the surface
Iodine Fuming
Ninhydrin
&
Physical Developer
LATENT PRINTS
• Non-porous sample
• Thumbprint found on
metal latch
LATENT PRINTS
Powdering
• Use the powder that provides the best
contrast with the background for
photography purposes, but black and white
are typically used
• Applied with brushes and other application
instruments (magnetic wands, cotton
fabric).
LATENT PRINTS
Regular Powders
Most commonly used
for processing
prints on windows,
counter-tops,
television sets,
metal file cabinets,
painted doors,
mirrors, broken
glass and metal
window frames.
LATENT PRINTS
Magnetic Powders
• Special surfaces i.e.,
– shiny magazine covers
– coated surfaces
– plastic storage or sandwich bags
LATENT PRINTS
Fluorescent powders
Regular or magnetic
Observe the development of the latent prints
with a UV light source while applying the
powders.
LATENT PRINTS
Lifting
Rubber lifters - lifting prints from curved or
uneven surfaces
Transparent lifting tapes – Reversed print
LATENT PRINTS
Chemical Processing
• Done at the laboratory
• Preferred method with porous surfaces
LATENT PRINTS
Physical Development Technique
• Small Particle Reagent (SPR)
– can be used on:
Paper, cardboard
New, rusty, & galvanized metal
Bricks, rocks, concrete,
Plastic, vinyl
Wood
Glass.
Super Glue Fuming
Super glue fuming print
LATENT PRINTS
Chemical Development Techniques
1.
2.
3.
4.
5.
Ninhydrin - porous surfaces (paper,
cardboard, and wood)
Diazafluoren (DFO)- 2.5x more sensitive
than Ninhydrin alone
Sticky Side Powder - adhesive tapes &
labels
Iodine Fuming - paper surfaces, and hard
smooth surfaces
Cyanoacrylate Fuming - super glue
LATENT PRINTS
Dye Stains
• Sudan Black- develop
latent prints on smooth or
rough, nonporous
surfaces contaminated
with greasy, oily and
sticky substances
LATENT PRINTS
• Other Dyes
– Ardrox Fluorescent Dye – UV lamp
– TapeGlo Fluorescent Dye
– Amido Black - sensitive to blood proteins
– Crystal Violet
– Physical developer (PD)
LATENT PRINTS
Mechanical Methods
• Electrostatic Detection Apparatus (ESDA)
• X-ray Detection (lead powder)
• Vacuum Metal Deposition
LATENT PRINTS
Surface Effects -The use of two or more
methods in a sequence of processing
techniques.
– Sequencing of Print Development
(Smooth)
1.
2.
3.
4.
Visual examination using necessary light
Examination with specialized light sources (UV)
Dust with non-magnetic powder
Magnetic powder dusting and or fluorescent
powder
5. Fluorescent Dye staining
LATENT PRINTS
• Sequencing of Print Development
(Porous surfaces)
1.
2.
3.
4.
5.
6.
7.
Visual examination
Fluorescent examination
Iodine fuming
Magnetic powder
DFO
Ninhydrin
PD
LATENT PRINTS
Latent Prints on Skin - can be washed away
with water excreted through perspiration.
With homicide victims, the skin has often
been exposed to harsh conditions, such as
mutilation, contamination with body fluids,
weather effects, and decomposition
LATENT PRINTS
Latent Prints in Blood Leuchomalachite Green - used to stain
fingerprints in blood that can be
photographed
Amido Black - traditional treatment for blood
prints.
*Chemical processing should only be carried
on blood if visual techniques fail
AFIS (Automated Fingerprint
Identification Systems)
The Integrated
Automated Fingerprint
Identification System,
(AFIS)
National fingerprint and
criminal history
system maintained by
the Federal Bureau of
Investigation (FBI),
Criminal Justice
Information Services
(CJIS) Division.
Automated Fingerprint
Identification Systems
• The introduction of
AFIS in 1997 has
allowed fingerprint
techs to scan
fingerprint images
into the database for
easy storage,
retrieval, and
comparison.
AFIS (Automated Fingerprint
Identification Systems)
•The AFIS provides
automated fingerprint
search capabilities,
latent searching
capability, electronic
image storage, and
electronic exchange
of fingerprints and
responses, 24 hours a
day, 365 days a year.
•As a result of
submitting fingerprints
electronically, agencies
receive electronic
responses to criminal
ten-print fingerprint
submissions within
two hours and within
24 hours for civil
fingerprint
submissions.
Automated Fingerprint
Identification Systems
LiveScan Fingerprinting
LiveScan is inkless
electronic fingerprinting.
The fingerprints are
electronically transmitted
to the Department of
Justice (DOJ) for
completion of a criminal
record check.
Digital Imaging for
Fingerprint Enhancement
• Technology can enhance the
condition of the prints, which
are lifted from the crime
scene
• The advancements in
computers has greatly
improved the fingerprint
identification process
• Software has been developed
which can now accurately
analyze the print and
eliminate unwanted
background materials, which
can impede the latent images
Automated Fingerprint
Identification Systems
• A trained technician scans your
fingerprints using an Identix
TouchPrint 600™ LiveScan. The
electronic fingerprinting
appointment takes five
to ten minutes and your
prints are immediately
available for electronic
transmission to the
appropriate FBI-Certified
channeling agencies for
background processing.
Automated Fingerprint
Identification Systems
• AFIS has changed the way
criminal investigators
operate, allowing them to
spend less time developing
suspect list and more time
investigating the suspects
generated by the computer.
• The AFIS makes no final
decisions on the identity of a
fingerprint, leaving this
function to the eyes of a
trained examiner.
Automated Fingerprint
Identification Systems
What are the benefits of LiveScan?
• Live Scan will avoid many of the problems associated
with ink prints, such as smudging, smearing, and over or
under inking.
• A major benefit of Live Scan is in processing speed
since nearly all of those without criminal records are
done within 72 hours and up to 30 days if there is a
criminal record.
• Rolled ink prints (traditionally submitted on a fingerprint
card) can take 10 to 12 days to process (plus mail time)
and up to 60 days if there is a criminal record.
John Dillinger tried to burn off his fingerprints with acid but even
this failed to do so!
FINGERPRINTS
The End