Fingerprints

What are the most important fingerprint factors

Uniqueness and permanece

Criminal purpose of prints

Link a subject to a crime
Associate physical evidence with a subject

Civil purpose of prints

Identification

Types of impressions found

Plastic

Plastic prints

Soft impressions made when finger is pressed against a soft surface

Latent prints

Hidden impressions from residues left behind by fingers

Patent

Visible prints

Alphonse Bertillon

Father of Anthropometry

Sir William Herschel (1856)

first European to use fingerprinting and recognize it for identification purposes

Henry Faulds

Application of fingerprints for criminal identification

Sir Francis Galton

First to note ridge characteristics

discusses uniqueness and permanence

Juan Vucetich

developed a fingerprint classification system

solved first case based on fingerprint evidence (Rojas case)

Rojas Murders

Woman murdered two sons and cut herself

Jennings Case

first higher court ruling on print evidence

Fingerprint residue composition

Sweat

eccrine glands

Produce sweat

99% water

sebaceous glands

oil glands

How are impressions deposited on a surface?

When a surface is touched you leave a reproduction of the friction ridges on that surface

Reasons for the absence of identifiable impression?

Substrate

ACE-V method

analysis

Analysis

Is there enough info in the impression. Level of detail

Comparison

Side by side assessment

Evaluation

Using education/experience to form a conclusion

Verification

Verify your findings with someone else

Conclusions following a comparison

Identification

Father of light energy

Roland menzel

AFIS

Automated Fingerprint Identification System

search unk impressions against a database of known records

NGI

Next Generation Identification

replaced IAFIS

what does no hit mean?

• subject is not in AFIS
• records were removed
• latent is poor quality
• known impression is poor quality
• latent impression is outside the area covered by fingerprint cards

advantages of indanedione v ninhydrin

it fluoresces and provides contrast on multi colored items

porous

absorbs moisture

nonporous

does not absorb moisture

What area of friction ridge detail does AFIS/NGI search?

fingers and palms

why is it necessary to wear goggles when utilizing an ALS

to visualize fluorescence, they block the emission of projected light, the excitation source is filtered b the goggles and allow the fluorescent color to pass through, for protection

why do you follow sequential processing methods

to minimize destruction

Superglue fuming

uses heat

powders

adheres to aqueous component and fatty deposits

iodine fuming

a technique for visualizing latent fingerprints by exposing them to iodine vapors that react with fats

DFO

react with amino acids

indandione

will fluoresce

Ninhydrin

reacts with amino acids to produce a purple color

oil red o

useful on wet surfaces

Physical Developer

wet process