Transcript Chapter 7-Prints - Ardsley Union Free School District

The World of Prints (7)
Anatomical Evidence:
The Outside Story
Trace Evidence Analysis
• Definition:
– involves the comparison of small pieces of
evidence with a standard (often called an
exemplar)
Fingerprint History
• Chinese, 3000 years ago, fingerprints on legal
documents
• 8th Century Japan-Legal Documents
• 14th Century Persia-Government Papers
• Ancient Rome-Bloody handprint linked to killer
• William Herschel 1800s (English civil servant
working in India) required Indians “sign”
documents with fingerprint.
• Henry Fauld 1800s (Scottish physician)
Fingerprints important in criminal investigations
History
• Francis Galton (1892) Published
“Fingerprints”-Science of Fingerprints
• Bertillon System supplemented with prints
• Sir Richard Henry (1897)-Developed
classification system and means of
accusation and filing.
• Bertillon System ditched with William West
Case (1903)-Fingerprints used in U.S.
Prisons
Flawed Bertillon System
Flawed Bertillon System
History
• 1900s fingerprints used on civil service
applications
• Mid 1900s used by police forces
•1930 National fingerprint file set up in
America by the FBI.
What is a fingerprint?
Fingerprints
• Fingerprints are formed underneath the skin in the
dermal papillae.
• As long as that layer of papillae is there, fingerprints
will always come back, even after scarring or
burning.
Latent Prints=Invisible Prints
When you touch
something, you leave
perspiration, oils, amino
acids
Skin Ridge Purpose
Skin Ridge Purpose
• Provide Firm Grasp
• Resist slippage of feet
Ridges
• Approximately 2,700 ridge "units" per
square inch of friction skin
Principles of Fingerprints in
Forensics
1. No two people have the same prints
(millions of prints collected over 90
years)
2. Fingerprints are genetic, develop as
fetus and remain the same for life and
sometime after death (exceptions related
to cancer drugs)
3. Fingerprints have patterns that allow
systematic classification
But what if I wear…
Gloves!
• Prints can be left through surgical
gloves. Gloves can also be turned inside out
to yield fingerprints from the inside surfaces.
Latent Leather Glove Print
• Leather leaves a print that is unique to that
glove and no other - leather comes from cow
skin, which is just as random as human skin.
Latent Cloth Glove Print
• Even cloth gloves, such as mittens, can leave
a distinctive print that can be traced back to
the mitten that made it.
Ridge types
65%
5%
30%
150 Individual ridge characteristics/
fingerprint
Prints and Ancestors

People of African ancestry tend to have
frequent arches.
 People of European background tend to
have frequent loops.
 People of Asian ancestry tend to have a
fairly high frequency of whorls
Minutia=Ridge Characteristics
Minutiae Points
Most courts require 14-16 matched
minutiae for a positive match
Sub classifications
Arches
• Plain Arch
– No significant core
– Lines come in from one
side and exit other side
without much change in
pattern
Arches
• Tented Arch
– Line type quickly rises
and falls at steep
angle
Deltas and Print Patterns
• Archs—no deltas
• Loops-one delta
Deltas:
• A place where two lines run side by side and
then diverge with a significant recurving line
which passes in front of the delta
A triangle is formed
Loops / Deltas
Loops:1 or more ridges entering from the side of the print,
recurving and exiting from the same side. Opens toward little finger
its ulnar and toward thumb it’s radial.
Loops / Deltas
Loops: core of loop is approximately the center; see blue box
Deltas: see red box
Ridge Count
Ridge Count: the number of lines intersected when a line is
drawn from the delta to the core
Whorls
• There are two deltas
• Several types
– Plain
– Central Pocket
– Accidental
– Double Loop
Whorls
• Plain Whorl
– Consists of one or more
ridges which tend to make
a complete circuit
– If a line is drawn between
the two deltas, it must
intersect at least one
recurving ridge within the
inner pattern
Whorls
• Plain Whorl
– Consists of one or more
ridges which tend to make
a complete circuit
– If a line is drawn between
the two deltas, it must
intersect at least one
recurving ridge within the
inner pattern
Whorls
• Plain Whorl
– Consists of one or more
ridges which tend to make
a complete circuit
– If a line is drawn between
the two deltas, it must
intersect at least one
recurving ridge within the
inner pattern
Whorls
• Central Pocket Whorl
– DOES NOT consist of a
ridge that makes a
complete circuit
– If a line is drawn between
the two deltas, it does not
intersect a recurving ridge
within the inner pattern
Whorls
• Central Pocket Whorl
– DOES NOT consist of a
ridge that makes a
complete circuit
– If a line is drawn between
the two deltas, it does not
intersect a recurving ridge
within the inner pattern
Whorls
• Central Pocket Whorl
– DOES NOT consist of a
ridge that makes a
complete circuit
– If a line is drawn between
the two deltas, it does not
intersect a recurving ridge
within the inner pattern
Whorls
• Double Loop Whorl
– Consists of two distinct,
separate, loop formations
– Has two deltas
• Loops have separate and
distinct shoulders
Whorls
• Double Loop Whorl
– Consists of two distinct,
separate, loop formations
– Has two deltas
• Loops have separate and
distinct shoulders
Forensic Fingerprints
38
Henry System of Classification
Primary Classification:
Henry (FBI) System - all prints fall into one
of 1024 groups
Pair up fingers on hands
Determine whorls (list numerically)
10 finger system
Henry System of Classification
R. Index
R. Ring
R. Thumb
R. Middle
L.Thumb
L. Middle
L. Little
R. Little
L. Index
L. Ring
•
Step 1: Set up these fractions
•
Step 2:
Whirls 1st Column fingers=16
2nd Column Fingers= 8
3rd Column Fingers= 4
4th Column Fingers= 2
5th Column Fingers= 1
•
Step 3: Tally Numbers
Henry System of Classification
• Example
– Suppose right index is whorl
– Suppose right middle is whorl
– All others are loops
16+0+0+0+0+1 = 17
0+8+0+0+0+1 =
9
Can You Change Fingerprints?
Can You Change Fingerprints?
• Not all patterns on hand!
• Needs wound down 2 millimeters into skin
• Fingerprints are formed underneath the skin
in the dermal papilae. As long as that layer
of papilae is there, fingerprints will always
come back, even after scarring or burning
• Much scaring makes you more individualistic
John Dillinger
SCAR
TISSUE
Before Acid
After Acid
Fingerprint Collection-Ink
Fingerprinting-Digital
AFIS
Search Speed= Minutes to search millions of prints
Automated Fingerprint Identification
Systems (AFIS)
• Automatic scanning devices convert FP
image to digital minutiae showing ridge
endings and bifurcation
• Stores and retrieves FP record
• Thousands of comparisons in seconds
• Produces list of file prints w/ closest
correlation
• National Institute of Standards and
Technology exchange of data between AFIS
systems
• Final verification by FP expert
NGI
• Next Generation Identification System
– Includes fingerprints, eye-scans, facial
imaging methods
– Faster identification possible
Fingerprints and Crimes
• Visible Prints
– Blood
– Paint
– Grease
– Ink
• Plastic prints
– Impressions in putty, wax, soap dust
• Latent Prints
– Hard-to-see remnants of perspiration and oils
Latent Fingerprint Development
• If hard, nonabsorbent
surface ex. Glass, tile
etc
– Fingerprint powders
– Soft brush
– Powder sticks to
perspiration
Latent Fingerprint Development
• If soft, absorbent
surface (ex. Paper,
cloth)
– Iodine crystal fuming
– Crystal undergo
sublimation
– Not permanent
development
– Gold-brown
development
– Mech. Unknown
Latent Fingerprint Development
• If soft absorbent
surface
– Ninhydrine Spray
– Reacts with amino
acids in perspiration to
produce purple
development
Ninhydrin Method
• Colorless compound reacts with amino
acids in sweat to form a colored
compound.
R
NH2
O
C
COOO-
O
H
OH
N
OH
O
Ninhydrin
O
Ruhemann’s Purple
O
53
Latent Fingerprint Development
• Nonporous surfaces
(metals, tape, leather,
plastic bags
• Super Glue Fuming
– Cyanoacrylate fumes
– Produces white print after
polymerizing on print.
– The visible prints produced
are white, but are often
treated with a fluorescent
dye to improve visibility
Silver Nitrate
• Silver Nitrate dissolved in water or alcohol is sprayed on the
object surface
• Reacts with the chlorine found in the salt in perspiration
– Renders the print inert to other chemical processes by creating an
insoluble solid (AgCl)
• Two step process
– Spraying or dipping the object in silver nitrate
– Developing the print with sunlight or a carbon vapor light
• Permanently stains object
Latent Fingerprint Development
• Lasers and
Fluorescence
– Natural fluorescent
components in sweat
that can be enhanced
with chemicals and
observed with laser
light
Latent Fingerprint Development
• Alternate light source
( quartz halogen,
xenon)
– Focused light along
fiber optic cables
RUVIS
• See latent
fingerprints before
development
Sticky side Powder
Preservation of prints
Photography
• Ultraviolet Digital Camera
for fingerprint collection D5UV
is a high-performance and
portable ultraviolet digital
camera system for fingerprint
collection. You can view and
search fingerprints from the
LCD screen of the D5UV. You can focalize
quickly and accurately and get high quality
images.
Preservation of prints
• Lifting Prints
Footnote
“Cancer patient held at airport for missing
fingerprint” (Reuters News Service)
• Side-effect of cancer drug Capecitabine
• palms or soles of the feet and the skin can peel,
bleed and develop ulcers or blisters -- or what is
known as hand-foot syndrome
Lip Prints
• Lip print lands Peeping Tom in jail
The Associated Press
• NEWPORT NEWS, Va. (AP) - This peeper's pucker landed him in
jail.
• Robert Neal Smith, 41, was sentenced to five months in jail Friday
after pleading guilty to peeping into his neighbor's windows. He was
charged with five counts of being a Peeping Tom after his lip prints
matched ones left on a window in August.
• Police had lifted the impression in September and obtained a search
warrant for Smith's lip marks. The state crime lab claimed the two
were a match.
• Smith told the General District Court judge he was drinking heavily
when he peeped into his neighbors' homes. At one point he was
chased by a woman's husband and another woman caught him
tampering with her window screen.
Lip Prints
• The five basic types
of lip prints used by
forensic scientists
are:
Lip Prints
• Cheiloscopy=study of lip prints
• Ancient Egyptians used henna to paint lips a
reddish purple hue
• Used mercuric plant dye called fucus for lip
rouge
• Can extract DNA from lip prints
• Lipsticks appeared first in the city of Ur near
Babylon 5000 years ago
• Lipstick first mass produced in tubes in 1915
• Differences found between man and women lip
prints
Foot Prints