History of Fingerprints

Transcription

1 Fingerprints

2 History of Fingerprints Johann Christoph Andreas Mayer 1788 First scientist to recognize fingerprints were unique William Herschel 1856 Began the collecting of fingerprints Alphonse Bertillon 1879 Created a way to identify criminals

3 History of Fingerprints Sir Francis Galton 1888 Developed the classification system for fingerprints that is still in use today Ivan (Juan) Vucetich 1891 Improved fingerprint collection by adding all 10 fingerprint impressions Devised a system that divided fingerprint records into groups based on their pattern

4 What Are Fingerprints Fingerprints form on the fetus at 10 weeks All fingers, toes, feet, and palms are covered in small ridges When these ridges press against things they leave a mark

5 Classification of Fingerprints Three classifications Loops 65% of population Whorls 30% Arches 5% LOOP WHORL ARCH

6 Loops Core center of a loop Delta triangular region located near a loop Enter from either the right or left and exit from the same side they enter (radial loop opens toward the thumb side, ulnar loop opens toward the pinkie side)

7 Whorls Look like a bulls-eye with two deltas (triangles) Divisions of whorls Plain whorl 24% Central pocket loop whorl 2% Double loop whorl 4% Accidental whorl 0.01%

8 Plain Whorl Has one or more ridges that make a complete spiral Has two deltas; line drawn between them cuts at least one ridge in the inner pattern is touched or cut by the line`

9 Central Pocket Whorl Has one or more ridges that make a complete circle Has two deltas, line drawn between them does not touch any ridge in the inner pattern

10 Double Loop Whorl Has two separate loop formations and two deltas

11 Accidental Whorl Has two or more deltas and is a combination of two of the other patterns (but not the plain arch)

12 Arches Two different types of arches Plain arch 4% Tented arch 1%

13 Plain Arch Shows ridges entering one side, rising in the center and flowing out the other side without making an angle Has no characteristics of the loop pattern

14 Tented Arches Forms an angle, or it may possess some characteristics of the loop pattern, such as a delta

15 Fingerprint Identification Minutiae the combination of details in the shapes and positions of ridges in fingerprints that make each unique these are also called ridge characteristics There are about 150 different ridge characteristics on an average fingerprint

16 Minutiae

17 Minutiae Endings point at which a ridge stops Bifurcation point at which one ridge divides into two Dots very small ridges Islands bigger than dots, occupy a middle space between two ridges Spur a notch protruding from a ridge Bridge small ridge joining two adjacent ridges

18 Legal Match In order to make a legal match, there must be 10 to 16 identical minutiae points on two prints

19 Types of Fingerprints at Crime Scenes Patent fingerprints visible prints Left on a smooth surface when blood, ink, or other liquid comes in contact with the hands and is transferred to that surface Plastic fingerprints actual indentations left in some soft materials like clay or wax Latent fingerprints hidden prints Caused by the transfer of oils and other body secretions onto a surface Made visible by dusting with powders or by a chemical reaction

20 Fingerprint Forensic FAQ Can fingerprints be altered? NO How reliable is fingerprinting as a means of identification? Only as reliable as the people performing the testing. How are fingerprints analyzed? In 1999, the FBI developed the Automated Fingerprint Identification System (AFIS) takes ~ two hours to find a match if the person is in AFIS (47 million people are listed in AFIS

21 FAQ Continued How are latent fingerprints collected? Surfaces are dusted with a fine carbon powder that makes the print visible Tape is then used to lift and preserve the fingerprint The tape is placed on an evidence card, the date, time, location and collector are logged The fingerprints are also photographed prior to being lifted