Chapter 6 Powerpoint Flashcards by Kelly Dowd

Why can fingerprints be used for personal identification?

Unique

Persistent

Classifiable

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Changes in fingerprints only occur because of

injury

disease

decomposition after death

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Friction ridge skin

the skin on the fingertips, palms of hands, soles of feet

characterized by patterns of ridges and furrows (hills and valleys)

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Why are fingerprints classifiable?

Arches
Loops
Whorls

Variations and sub categories exist within these three patterns

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Fingerprints are:

persistant and unchanging

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Fingerprint patterns are formed during:

early embryonic gestation (8-12 weeks)

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Genetic composition may:

play a role in determining which patterns develop. but are not totally responsible

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Identical twins:

have the same genetic makeup but different fingerprints

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Minutiae

features present within patterns of fingerprints

Crucial to fingerprint examination

Individualizing characteristics

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Minutiae are formed by ridges:

ending abruptly (ending ridge)

splitting into two ridges (bifurcation)

being short (dot)

These are considered primary minutiae

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Nehemiah Grew

First person to study and describe ridges, furrows, and pores on the hand and foot surfaces.

First fingerprint pioneer

Published accurate drawings of finger patterns and palm areas

Made no mention of fingerprint uniqueness

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Marcello Malpighi

Researched the functions of the human skin

Observed ridges of palmer surfaces under microscope

Briefly mentioned ridge detail in his publications but did not talk about individuality

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Alphonse Bertillon

Devised the first scientific method of criminal identification, Anthropometry

System of bodily measurements for personal identification

11 measurements

Drawbacks: people gain and lose weight, inaccurate measurements taken by officers

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Will West v William West

Leavenworth Prison

Will West = new prisoner

Staff member thought he had entered the measurements before

Same measurements fit prisoner William West, already incarcerated

Looked similar

Not related to each other

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Juan Vucetich

Police department in Argentina

Value of fingerprints as a means of criminal identification

First recorded case: was murder in 1892

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Classification Systems are based on:

ten print fingerprint standards from criminals

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Classification Systems are not for:

search individual fingerprints to partial single prints

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AFIS

Automated Fingerprint Identification System

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Two principal applications for AFIS:

searching files for the presence of a ten print record

searching files for single prints from crime scenes

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Why are their different AFISs?

different vendors use different technologies

Different system are usually not compatible with one another

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Two Types of AFIS profiles held:

Known files (ten print records)

Unknown files/ Forensic Files (unsolved cases) –> can link cases when same print is submitted to unknown portion from different crimes

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FBI Criminal fingerprint database is:

IAFIS: Integrated AFIS

Why would we not find fingerprints at every scene?

gloves worn, wiped or smudged, item was not touched, environment, surface condition, subject

Makeup of fingerprints

5% water

1. 5% organic and inorganic materials (amino acids, creatine, fatty acids)

Three Types of finger impressions

latent, patent, plastic

Latent

invisible; made of perspiration and oils; need to be physically or chemically developed to be visible

Patent

visible prints made in blood, paint, grease, ink, etc. do not need to be developed to be visualized may be enhanced using chemical methods

Plastic prints

3D impression left in soft, pliable surface chocolate, butter, cheese, wax creates negative impression

Physical Development Methods for Fingerprints

Cyanoacrylate Ester Fuming (super glue) Fingerprint powder Fluorescent powder magnetic powder

Chemical Development for Fingerprints

Iodine Ninhydrin Indandione

Iodine

Reacts with starches, print will be brown in color use on porous surfaces affixed using heat will develop old prints unstable, must be photographed quickly

Ninhydrin

Reacts with amino acids, print will be purple in color Can be used after iodine use on porous surfaces

Indandione

reacts with amino acids use on porous surfaces fluoresces with ALS

Dye Stains

Use after CA fuming Fluorescence examination

Arch

simplest fingerprint pattern formed ridges that enter on one side and exit on the other No deltas Two types: plain and tented Does not have: looping ridge, upthrust, recurve

Delta

that point on a ridge at or nearest to the point of divergence to two type lines located at or directly in from of the point of divergence

Core

the approximate center of the pattern

Loop

one or more ridges enter upon either side, recurve, touch, or pass through an imaginary in between delta and core, and pass out upon the same side as they entered

Three basic requirements for a loop

sufficient recurve one delta ridge count across as looping ridge

Two types of loops

Ulnar and Radial

Ulnar loop

flow toward the ulna bone (pinky)

radial loop

flow toward the radius bone (thumb)

Whorl minimum requirements

two deltas, recurve in front of each delta

four types of whorls

plain central pocket double loop accidental

Plain whorl

one or more ridges which make a complete circuit two deltas at least one recurving ridge within inner pattern when imaginary line is drawn between two deltas

central pocket whorl

similar to a plain whorl imaginary line drawn from delta to delta must not touch a recurving ridge in front of the inner delta

double loop whorl

consists of two separate loop formations with two separate and distinct sets of shoulders and two deltas

The purpose of an examination is to:

determine the source of a print exclude the source of a print

ACE - V

Analysis Comparison Examination Verification

Analysis

The assessment of a print as it appears on a substrate Separate print into its components: substrate, matrix, development medium, distortion, etc. Establish level of details available Determine if print is sufficient for comparison purposes

Comparison

Determine whether details in two prints are in agreement based on: similarity sequence spatial relationship

Evaluation

Final determination made for agreement or disagreement of details present in the questioned and known prints

Verification

Independent examination by another examiner ACE methodology applied Blind v Non Blind

SWGFAST

Scientific Working Group on Friction Ridge Analysis, Study, and Technology