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Why can fingerprints be used for personal identification?
Unique Persistent Classifiable
Changes in fingerprints only occur because of
injury disease decomposition after death
Friction ridge skin
the skin on the fingertips, palms of hands, soles of feet characterized by patterns of ridges and furrows (hills and valleys)
Why are fingerprints classifiable?
Arches Loops Whorls Variations and sub categories exist within these three patterns
Fingerprints are:
persistant and unchanging
Fingerprint patterns are formed during:
early embryonic gestation (8-12 weeks)
Genetic composition may:
play a role in determining which patterns develop. but are not totally responsible
Identical twins:
have the same genetic makeup but different fingerprints
Minutiae
features present within patterns of fingerprints Crucial to fingerprint examination Individualizing characteristics
Minutiae are formed by ridges:
ending abruptly (ending ridge) splitting into two ridges (bifurcation) being short (dot) These are considered primary minutiae
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
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
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
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
Juan Vucetich
Police department in Argentina Value of fingerprints as a means of criminal identification First recorded case: was murder in 1892
Classification Systems are based on:
ten print fingerprint standards from criminals
Classification Systems are not for:
search individual fingerprints to partial single prints
AFIS
Automated Fingerprint Identification System
Two principal applications for AFIS:
searching files for the presence of a ten print record searching files for single prints from crime scenes
Why are their different AFISs?
different vendors use different technologies Different system are usually not compatible with one another
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
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)