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Environmental Science Wildlife Forensics

Environmental Science Wildlife Forensics. Identifying Fingerprints. Why are fingerprints important evidence?. Each person on the planet has a unique set of prints Even identical twins have different patterns A fingerprint can prove: A certain person was at the scene of a crime

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Environmental Science Wildlife Forensics

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  1. Environmental ScienceWildlife Forensics Identifying Fingerprints

  2. Why are fingerprints important evidence? • Each person on the planet has a unique set of prints • Even identical twins have different patterns • A fingerprint can prove: • A certain person was at the scene of a crime • They touched something that was used in a crime

  3. History of fingerprinting • Juan Vucetich: first used fingerprinting in criminal investigations • Anthropologist and police official in Argentina • 1891- he created first filing • 1892- made first positive ID of criminal • The murder of two children and stabbing of a mother • Mother survived, but latent print showed she was guilty • Dr. Henry DeForrest: pioneered use of fingerprinting in U.S. • Civil service exam in New York • NY state prison system

  4. What is a Fingerprint? • Fingertips have small ridges and grooves that create a unique pattern • Their purpose is to create friction • These ridges form early in fetal development • Never change • Skin is made of two layers • Outer epidermis • Worn off and replaced throughout life • Inner dermis • Holds oil and sweat glands to keep skin moist • Oil transfers when you touch an object

  5. Fingerprint Patterns • 3 Groups • Arches, Loops, Whorls • Each group has a different number of deltas • Place where ridges converge from three sides to form a triangle • Arches have none, Loops have one, and whorls have two

  6. Arches • Simplest patterns and have no deltas • Plain Arch • Moves across finger with no center point (core) or intersecting ridges • Tented Arch • The center core looks like a pole holding up a tent • NOT a delta

  7. Loops • The most common print pattern • Ridges enter/exit from same side • One delta • If you know which hand the print is from, you can determine radial or ulnar loop

  8. Whorls • 4 different types: • Plain whorl: looks like a ripple effect in water • Central pocket whorl: smaller center circles, outer ridges move to one side (loop-like) • Double loop whorl: Two separate loops wrapped together • Accidental whorl: very uncommon, combination of different loop and whorl patterns • The center of a whorl looks like a circle • Have two or more deltas

  9. Fingerprint Evidence • 3 Types of fingerprint evidence • Describe the surface the print was made on and how the print was made • 1) Latent print: mark left on a surface from the finger’s natural oil • Not clearly visible until another material reacts with oils • Most common method is dusting • 2) Visible print: made when fingertip is covered with some substance and leaves a mark • Can be seen without help from other materials • 3) Plastic impression: 3-D print made when finger is pressed into soft material that holds its shape • Clay, putty, grease, wet paint, wax, etc.

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