Fingerprint Analysis

Bud & Patti Bertino

Fingerprints Formation

• Skin produce secretions oil, salts

• Dirt combines with secretions

• Secretions stick to unique ridge

patterns on skin

Did You Know?

• Fingerprints are unique

• Form before birth in dermal papillae

• Never change

• Return after scarring or burning

History of

Fingerprinting

• B.C. Chinese first used fingerprints

• 1886 fingerprints for ID purposes

• 1891 first ‘10 card’

• 1902 first murder solved using

fingerprints

1891

University @ Lyon

Ferroprussinate was

used as the developer.

Source: Evidence

Technology, Nov-Dec 2007

First handprint

• 1905 U.S. Army uses fingerprints

• 1946 100 Millionth 10 card

• 1975 FBI introduces AFISAutomated

Fingerprint

Identification

System

• 2007 Department of Homeland Security has 63 million records

Types of Fingerprints

• Patent or Visible on smooth surfaces

• Latent or invisible

• Plastic: prints found in soft materials

such as soap

A famous set of prints

John

Dillinger

Making your ‘10 Card’

Who’s fingerprint?

Source: www.virtualsciencefair.org

Human

Chimp

Koala

Latent Fingerprints

• Treated with powders or chemicals

enhance ridge pattern

• Ninhydrin

• Super glue

• Iodine

How are latent prints obtained?

• Iodine fuming

• Ninhydrin

• Super glue

• Super glue

+NaOH

treatment

• Toxic & over-develops

• Toxic & fades in two

days

• Toxic

• Toxic

Method Effect

Fingerprints and Gloves

• Prints can be formed through surgical

gloves

• Prints left on the inside of gloves can be

lifted

Fingerprint Pattern Types

L(oops) A(rches) W(horls)

Loop 65% Core

Delta

One delta only

Loops

Two types:

Pinky side – ulnar

Thumb side - radial

Plain Arch

4 percentTented Arch

1 percent

Whorl Patterns

• Whorls occur in 30% of fingerprint patterns

PLAIN 24% CENTRAL POCKET 2%

Two deltas

Whorl Patterns

DOUBLE LOOP 4% ACCIDENTAL .01%

Fingerprint Patterns

• F.B.I recognizes eight basic

patterns

• Ten basic details within the

patterns (minutiae)

• 12 identical points were

necessary for a match

Balloon Thumbprint

Minutiae patterns

Ridge Minutiae

Identify some ridge patterns

Minutiae

Ending ridges

Bifurcations

Dots

Islands

Identify Minutiae patterns

CSI vs. The Real World

• AFIS (Automated Fingerprint Identification System) can search back 99 years

• Lack of standardization

• AFIS searches for a biometric pattern not a fingerprint! It matches chosen minutia patterns.

Source: The Forensics Teacher - Summer 2008

• Criminal, civilians, stock

brokers, civil servants, military

personnel, teachers, security

guards, etc., are included but

systems are not always linked.

• Latent database and cold cases

How Does AFIS Work?Fingerprint images are

scanned and digitized

Minutiae are coded

Minutiae are searched by

computerized matchers

Search candidates are

produced side-by-side on a

computer screen

Candidates are examined

Evidence Technology, 2012

Ten Card Print Crime Scene Print

Algorithm using MinutiaeReplaces point ID Uses computers

Faster More accurate

Fingerprint formed in soot.

Evidence Technology Magazine May-June 2008

What’s new?

Lift fingerprints from

Pills Feathers

Source: Evidence Technology Magazine Nov-Dec 07

Even from cadavers

Source: Evidence Technology Magazine Nov-Dec 07

Evidence Technology Magazine

September-October 2008, p30

Fingertips in

I.D. Enhancer Solution

Casting made of fingerprints in

silicone-rubber

A Match!

Orange fluorescent

powder viewed with

special camera filter

Electrical tape

both sides

Source: Evidence Technology Magazine Nov-Dec 07

Mobile cyanoacrylate fuming

Source: Evidence Technology Magazine Nov-Dec 07

Identity Recognition

• Fingerprints

• Facial recognition – within 10

years

• Iris scan – are no two alike?

To be determined and cannot

be used in court (as yet)

Matrix

scanners

Biometric Devices

Kiplinger Newsletter 11/12

Finger scanners

Free NIJ online sourcebook

Notice the scar

Fingerprints!

They’ll get you every time.