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Fingerprints

Fingerprints. “Fingerprints can not lie, but liars can make fingerprints.” — Unknown. Fingerprints. Recording Prints rolling inked prints Lifting Prints Powders-Black, white and fluorescent (nonabsorbent) Chemicals — ninhydrin, iodine, silver nitrate, cyanoacrylate(absorbent)

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Fingerprints

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  1. Fingerprints “Fingerprints can not lie, but liars can make fingerprints.” —Unknown

  2. Fingerprints Recording Prints • rolling inked prints Lifting Prints • Powders-Black, white and fluorescent (nonabsorbent) • Chemicals—ninhydrin, iodine, silver nitrate, cyanoacrylate(absorbent) Other Types of Prints • Palm, lip, teeth, eye, ear, voice, shoe and footprints Kendall/Hunt Publishing Company

  3. DactyloscopyThe study of fingerprints Kendall/Hunt Publishing Company

  4. Fundamental Principlesof Fingerprints • A fingerprint is an individual characteristic. UNIQUE • A fingerprint will remain unchanged during an individual’s lifetime. • Fingerprints have general characteristic ridge patterns that permit them to be systematically classified. Kendall/Hunt Publishing Company

  5. Arch An arch has friction ridges that enter on one side of the finger and exitthe other. They do NOT have deltas or cores. Types • Plain • Tented Kendall/Hunt Publishing Company

  6. Loop • A loop must have one or more ridges entering and exiting from the same side. Loops must have one delta. • Types • Radial—opens toward the thumb • Ulnar—opens toward the “pinky” (little finger) Kendall/Hunt Publishing Company

  7. Whorl • A plain or central pocket whorl has at least one ridge that makes a complete circuit. A double loop is made of two loops. An accidental is a pattern not covered by other categories. Whorls have at least two deltas and a core. • Types • Plain • Central Pocket • Double Loop • Accidental Kendall/Hunt Publishing Company

  8. Ridge Characteristics Minutiae—small ridge patterns • Ridge ending • Short ridge • Dot or fragment • Bifurcation • Double bifurcation • Trifurcation • Bridge • Island • Enclosure • Spur Kendall/Hunt Publishing Company

  9. Fingerprint Minutiae Kendall/Hunt Publishing Company

  10. Comparison There are no legal requirements in the United States on the number of points. Generally, criminal courts will accept 8 to 12 points of similarity. Kendall/Hunt Publishing Company

  11. Latent PrintsLAZY • Latent fingerprints are those that are not visible to the naked eye. These prints require development for them to become visible. • . Kendall/Hunt Publishing Company

  12. Developing Latent Prints • Powders-black (glass, tile, metals) • Chemicals (paper, cloth) • Iodine—fumes react with oils and fats to produce a temporary yellow brown reaction. • Ninhydrin—reacts with amino acids to produce a purple color. • Silver nitrate—reacts with chloride to form silver chloride, a material which turns gray when exposed to light. • Cyanoacrylate—“super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit. Kendall/Hunt Publishing Company

  13. Iodine Fingerprint Kendall/Hunt Publishing Company

  14. Ninhydrin Fingerprint Kendall/Hunt Publishing Company

  15. Cyanoacrylate Fingerprints Kendall/Hunt Publishing Company

  16. Other Prints Palm—friction ridges can be identified and may be used against suspects. Kendall/Hunt Publishing Company

  17. Other Prints Footprints are taken at birth as a means of identification of infants. Kendall/Hunt Publishing Company

  18. Patent PrintsPlain to See Kendall/Hunt Publishing Company

  19. Plastic Prints-3-D Kendall/Hunt Publishing Company

  20. Other Prints Lips—display several common patterns • Short vertical lines • Short horizontal lines • Crosshatching • Branching grooves Kendall/Hunt Publishing Company

  21. Other Prints Teeth—bite marks are unique and can be used to identify suspects.

  22. Other Prints The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes. Kendall/Hunt Publishing Company

  23. AFIS • The Automated Fingerprint Identification System - a computer system for storing and retrieving fingerprints • Began in the early 1970’s to: • Search large files for a set of prints taken from an individual • Compare a single print, usually a latent print developed from a crime scene • By the 1990’s most large jurisdictions had their own system in place. The problem - a person’s fingerprints may be in one AFIS but not in others • IAFIS—the FBI’s Integrated Automated Fingerprint Identification system which is a national database of all 10-print cards from all over the country Kendall/Hunt Publishing Company

  24. More about Prints For additional information about prints and crime, check out Court TV’s Crime Library www.crimelibrary.com/criminal_mind/forensics/fingerprints/1.html Kendall/Hunt Publishing Company

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