Chapter 6 Fingerprints

Transcription

1 Chapter 6 Fingerprints Vcabulary: Arch: a fingerprint pattern in which the ridge pattern riginates frm ne side f the print and leaves frm the ther side Cre: Delta: a triangular ridge pattern with ridges that g in different directins abve and belw a triangle Fingerprint: Latent Fingerprint: a hidden fingerprint made visible thugh the use f pwders r ther techniques Lp: Minutiae: the cmbinatin f details in the shapes and psitins f ridges in fingerprints that make each unique; als called ridge characteristics Patent Fingerprint: a visible fingerprint that happens when fingers with bld, ink, r sme ther substance n them tuch a surface and transfer the pattern f their fingerprint t that surface Plastic Fingerprint: Ridge Pattern: the recgnizable pattern f the ridges fund in the end jints f fingers that frm lines n the surfaces f bjects in a fingerprint. They fall int three categries: arches, lps and whrls Ten Card: Whrl: 1

2 By the end f this chapter yu will be able t: discuss the histry f fingerprinting describe the characteristics f fingerprints and fingerprinting minutiae explain when and hw fingerprints are frmed describe what causes fingerprints t be left n bjects identify the basic types f fingerprints describe hw criminals attempt t alter their fingerprints determine the reliability f fingerprints as a means f identificatin describe the Integrated Autmated Fingerprint Identificatin System (IFAIS) explain hw fingerprint evidence is cllected describe the latest identificatin technlgies determine if a fingerprint matches a fingerprint n recrd use the prcess f lifting a latent print Histrical Develpment In ancient Babyln (dating back t B.C.), fingerprints pressed int clay tablets marked cntracts. The earliest written study (1684) is Dr. Nehemiah s paper describing the patterns he saw n human hands under a micrscpe, including the presence f ridges. In 1788, Jhann Mayer nted that the arrangement f skin ridges is never duplicated in tw persns. He was prbably the first scientist t recgnize this fact., in 1856, began the cllectin f fingerprints and nted they were nt altered by age. created a way t identify criminals that was used in 1883 t identify a repeat ffender. 2

3 In 1888,, and, develped the fingerprint classificatin system that is still in use in the United States. In 1891, imprved fingerprint cllectin. He began t nte measurements n identificatin cards, as well as adding all ten fingerprint impressins. He als invented a better way f cllecting the impressins. Beginning in 1896,, with the help f tw clleagues, created a system that divided fingerprints int grups. Alng with ntatins abut individual characteristics, all ten fingerprints were imprinted n a card (called a ten card). What Are Fingerprints?. These ridges are arranged in cnnected units called, r, ridges. Natural secretins plus dirt n these surfaces leave behind an impressin (a print) n thse bjects with which we cme in cntact. Frmatin f Fingerprints An animal s external tissue (skin) cnsists f (a) and (b) an. The creatin f fingerprints ccurs in a special layer (the basal layer) in the epidermis where new skin cells are prduced. Fingerprints prbably begin frming at the start f the 10 th week f pregnancy. 3

4 Characteristics f Fingerprints There are 3 general fingerprint distinctins: Abut % Abut % Abut % f the ppulatin Characteristics f Fingerprints Frensic examiners lk fr the presence f a (the center f a whrl r lp) and (triangular regins near a lp). A ridge cunt is anther characteristic that distinguishes ne fingerprint frm anther. The cunt is made frm the center f the cre t the edge f the delta. Basic patterns can be further divided:. 4

5 Types f Fingerprints There are 3 types f prints that investigatrs lk fr at crime scenes: Patent fingerprints are Plastic fingerprints are. Latent fingerprints are Minutiae Patterns characteristics f ridge patterns Ridge ending Shrt ridge Dt r fragment Bifurcatin Duble bifurcatin Trifurcatin Bridge Island Enclsure Spur Cmparisn There are n legal requirements in the United States n the number f pints. Generally, criminal curts will accept t pints f similarity. Fingerprint Frensic FAQs Can fingerprints be erased? Is fingerprint identificatin reliable? 5

6 AFIS Is fingerprint matching carried ut by cmputers in a matter f secnds? N, but the FBI s Integrated Autmated Fingerprint Identificatin System (IAFIS r AFIS) can prvide a match in 2 hurs fr the prints in its Master File. The - a cmputer system fr string and retrieving fingerprints Began in the early t: Search large files fr a set f prints taken frm an individual By the 1990 s mst large jurisdictins had their wn system in place. The prblem IAFIS the system which is a natinal database f all 10-print cards frm all ver the cuntry Fingerprint Frensic FAQs Hw are latent fingerprints cllected? 6

7 The Future f Fingerprinting Trace elements f bjects that have been tuched are being studied t help with the identificatin f individuals. 7