Criminalistics II

Personal Identification first developed

by Alphonse Bertillon. Anthropometry
(bertillonage) - 11 measurements made of the human anatomy

Herschel

in India used fingerprints as a form of signature (1858); proposes a fingerprint system to ID prisoners (1877)

Henry Fauld

in Japan, published a treatise (1880) on the potential application of fingerprinting to personal identification

Francis Galton

published a textbook on fingerprints (1892) - no two prints are alike; British gov’t adopts fingerprinting as a supplement to bertillonage

Dr. Juan Vucetich

developed a 10-digit fingerprint classification system to organize fingerprints (argentina 1891)

Sir Edward Henry

developed a 10-digit fingerprint classification system in 1897 that was adopted by Scotland Yard in 1901 (still used today)

what was used before fingerprints

bertillonage (body measurments)

People v Jennings

Fingerprints admitted as evidence in U.S. court in 1910

in 1924 FBI set up

its first fingerprint data base

AFIS meaning

Automated Fingerprint Identification System

A fingerprint is

an individual characteristic. No two fingers have yet been found to possess identical ridge
characteristics.

fingerprints differentiated by

ridge characteristics (minutiae) in their type,
number & location.

To determine if two fingerprints are identical

10 to 16 points of comparison needed

Fingerprints are a reproduction of

friction skin ridges found on the palm side of the fingers and thumb

friction ridge purpose

to provide our bodies with a firmer grasp and resistance to slippage

layers of the skin

epidermis, dermis, and dermal papillae

dermal papillae

outermost layer of skin

dermis

inner layer of the skin

dermal papillae

separates the dermis and the dermal papillae. The shape of it determines the form and
pattern of the fingerprint ridges on the surface of the skin

dermal papillae develops

in the human fetus and remain unchanged throughout life (friction ridges also remain unchanged)

how does scarring affect fingerprints

can only change a few minutiae and provide additional individualizing characteristics.

skin ridges all have

a row of pores where perspiration from the
sweat glands are discharged (not oily). Oily deposits from hairier portions of skin leave a thin film on skin

General classifications of fingerprints

loops, whorls, arches

Loops

most common. One or more ridges
enters one side, curves, exits same
side. Two types: radial and ulnar

radial loop

opens towards the thumb

ulnar loop

opens towards the little finger.

arch

least common. One or more ridges enters one side, rise to a wave, exits the opposite side. Two types: tented and plain

plain arch

smooth curved wave in the
center; exits smoothly on the opposite
side

tented arch

variation of plain arch in which the ridges at the center are thrust upward in a more abrupt manner.

whorl

ridges form a circular pattern. Five types: plain, central pocket loop, twinned (double) loop, accidental, lateral pocket loop

plain whorl

one or more ridges form a complete revolution around the center; have two or more deltas.

central pocket loop

variation of plain whorl; ridges tend to form a loop pattern which recurves & surrounds a whorl in center

double (twinned) loop

two separate loops surround each other

accidental

doesn’t conform to any of the other whorl specifications

lateral pocket loop

one loop serves as the side pocket for the other loop. Pocket formed by downwards bending on one side of the ridges

delta

a triangle-shaped area of a fingerprint where the ridge formation changes direction

how does AFIS work

by using automatic scanning devices to convert the image of a single fingerprint into digital minutiae that contains data showing ridges at their points of termination and their bifurcations

Bifurcation

the branching of singular ridges into two ridges

fingerprints formed from

residue from the friction ridge skin surface is transferred to a touched object (Locard exchange principle)

patent fingerprints

prints that can be seen with the naked eye. Two type: visible and plastic

latent fingerprints

require development method in order to be visualized.

visible fingerprints

made by fingers stained with colored
material (blood, ink, paint, grease, or dirt). Photograph directly

plastic prints

a 3D indentation. Can be formed by pressing the friction ridges of the fingers onto a soft surface (wax, putty, tar, soap, butter, or clay). Photograph but sometimes do a cast

what makes up basis of latent prints

the non oily secretions from the sweat glands in friction ridge skin

to individualize fingerprints

identify central pattern and minutiae

Fingerprint minutiae types

bifurcation, island, dot, short ridge, ridge ending, trifurcation, bridge, angle, converging ridges, diverging ridges

ACE-V fingerprint order

analysis, comparison, evaluation, verification

is fingerprints admissable

yes because fingerprints although problematic,
is still probably far more probative than much evidence that we do permit (ex eyewitness testimony)

physical methods for latent print development

powder dusting, laser analysis, x-ray analysis, vacuum coating

powder dusting (latent prints)

colored/fluorescent/magnetic powders

laser analysis ( (latent prints)

argon laser fluoresces print which is then photographed. The Riboflavin and pyridoxin within the residue is what causes the fluorescence. Requires a blocking filter

x-ray analysis (latent prints)

electron emission radiography

vacuum coating (latent prints)

deposition of a thin film of metal onto the print; used for prints on fabric, paper etc.

chemical methods for latent print development

required for prints on soft, porous surfaces. Types are iodine fuming, ninhydrin spraying, silver nitrate exposure, and super glue fuming

Iodine fuming

detects fatty oils left behind in sweat; yellowish-brown prints observed are temporary

Ninhydrin spraying

detects amino acids in sweat; purple-blue print formed; works well on old prints on paper

Silver nitrate exposure

detects salt (chloride ion) in sweat; developed print is reddish brown

super glue fuming

cyanoacrylate; forms a white colored pattern

palm and sole prints have

Friction ridge patterns similar to
fingerprints and are processes in the same way. Can potentially be individualized

palmar zone

the palm of hand

thenar zone (radial)

lower portion under thumb

hypothenar zone (ulnar)

lower portion under little finger

carpal delta (wrist)

lowest portion closest to wrist

calcar zone

the heel of the foot

ball pattern zone

the side of the big toe

plantar pattern zone

little toe side of ball

tread zone

the center of the foot

tibial pattern zone

center of arch (flat feet)

fibular pattern zone

farthest away end of tread

bitemarks can be compared to exemplars when

its deep, pronounced, clearly visible, fresh, well preserved, & with unusual characteristics

subdivision of odontology

bitemark comparisons

odontologists believe

dental structures are unique and can have individual characteristics

when comparing bitemarks

Compare teeth alignment/positions, relationships, irregularities and remember marks can change shape and size over time (depending on material) so do photo immediately and periodically afterwards

characteristics of teeth

resistant to damage, heat, decomposition so good for identifying dead bodies

miscellaneous pattern types

forensic anthropolgy (study of bones), cheiloscopy (study of lip prints these are individual), ear prints (may be individual), tattoos, branding patterns, anthropometry

tracks and trails

patterns for comparison and individualization

classification parameters of tire tracks

wheelbase and front and rear track width. Can help identify wheel manufacturer

wheelbase

distance between the front and rear axles of a vehicle

front and rear track width

the length of an axle; the distance between centerlines of tread imprints on the ground.

Footwear Outsole Patterns

created from shoewear

Footwear Outsole Pattern Impression prints

in soft material such as mud, sand, mortar, snow, etc

Footwear Outsole Pattern Residue prints

made on solid surfaces by dust, blood, etc

when documenting footwear prints

document with a photo and have a scaled ruler

electrostatic lifting

is for dry shoeprints in dust impressions

how electrostatic lifting works

a lifting film that is placed over a surface bearing a dust print impression is charged. The dust particles are attracted to the film and the film stores the electrostatic charge (retaining the print). It is viewed with an oblique light source

surfaces electrostatic lifting is used on

linoleum tile, paper, seat covers, wood

casting materials for shoeprints

plaster of paris, dental stone, wire mesh (for strength)

plaster of paris

hydrated calcium sulfate used for shoeprint casting

dental stone

preferred shoeprint casting method for size comparisons since it has low expansion factor

shoeprint casting in snow difficulties

low contrast in images and casting materials may melt snow

techniques for shoeprint casting in snow

Highlighting with colored aerosol
sprays, sulfur casting, and combining snowprint wax and dental stone

effects of Highlighting shoeprint in snow with colored aerosol spray

easier to capture details photographically (Snow print wax is colored red or gray auto body primer)

Snowprint Wax with dental stone method involves

Aerosol spray coats & hardens the
impression. This protects the impression details during casting with dental stone

sulfur shoeprint in snow casting technique

Use crystalline sulfur, melted to just
above melting point and pour over impression. The recrystallization captures impression details. Success based on environment

footwear outsole databases

Allows identification of footwear type. Computerized databases of known
outsole patterns. Give you information on manufacturer, model, size, dates of
production (class characteristics)

exemplar preparation of footwear outsole pattern print

you don’t directly compare the suspects shoe to the evidence print, you make a print from the suspects shoe (the exemplar) for comparison.

footwear outsole pattern exemplar preparation methods

Inked Prints, Oil/Black Powder Prints, Roller Transport Cleaner Film with
Magnetic Powder/Black Toner, Chemical Development

for inked exemplar prepared prints

a thin coat of ink is put on the outsole and a series of papers are placed on the ground for person to walk on

for oil/black powder exemplar prepared prints

Apply a thin layer of oil to outsole, step on
a white paper substrate, then dust the oil
print with black powder

for Roller Transport Cleaner Film with
Magnetic Powder/Black Toner exemplar prepared prints

Apply a thin layer of 10% glycerol to the
outsole, then dry it; apply the powder/toner,
then step onto the moistened RTCF