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Chapter 4: Fingerprints HAMM CASE Mark Twain story from text, p 134.

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Presentation on theme: "Chapter 4: Fingerprints HAMM CASE Mark Twain story from text, p 134."— Presentation transcript:

1 Chapter 4: Fingerprints HAMM CASE Mark Twain story from text, p 134

2 Chapter 4 Kendall/Hunt Publishing Company 1 Fingerprints  Why fingerprints are individual evidence.  Why there may be no fingerprint evidence at a crime scene.  How computers have made personal identification easier. Students will learn:

3 Chapter 4 Kendall/Hunt Publishing Company 2 Students will be able to:  Define the three basic properties that allow individual identification by fingerprints.  Obtain an inked, readable fingerprint for each finger.  Recognize the general ridge patterns (loops, whorls, and arches)  Identify friction ridge characteristics and compare two fingerprints with at least ten points of identification.  Explain the differences among latent, plastic, and visible fingerprints.  Develop latent prints (make them visible) using physical and chemical methods. Fingerprints

4 Chapter 4 Kendall/Hunt Publishing Company 3 Fingerprints Recording Prints  rolling inked prints  primary identification number Lifting Prints  Black, white and fluorescent powder  Chemicals—ninhydrin, iodine, silver nitrate, cyanoacrylate Other Types of Prints  Palm, lip, teeth, eye, ear, voice, shoe and footprints

5 Chapter 44 Dactyloscopy The study of fingerprints Historically  1800 BC prints in Babylonian clay tablets  Over 3000 years ago, Chinese may have used them  1684, Dr. Nehemiah noted ridges  1788, Mayer said they were unique  1823, Purkyn described loops whorls, arches  1856, William Herschel— required Indians to put their fingerprints on contracts, and also as a means of identifying prisoners  Henry Faulds— claimed that fingerprints did not change over time and that they could be classified for identification  1879, Alphonse Bertillon— proposed body measurements as a means of identification; termed anthropometry  1888, Francis Galton— developed a primary classification scheme based on loops, arches and whorls.  1896, Edward Richard Henry— in collaboration with Galton instituted a numerical classification system

6 Chapter 4 What was wrong? Everyone KNOWS fingerprints are individual and can be matched  All of this developed historically  Some of it before the scientific method  All aspects were not proven scientifically with controlled experiments and published results  Daubert hearings challenged what was long accepted  So now they are proving everything that was taken for granted 5

7 Chapter 4 Kendall/Hunt Publishing Company 6 Fundamental Principles of Fingerprints  A fingerprint is an individual characteristic.  A fingerprint will remain unchanged during an individual’s lifetime.  Fingerprints have general characteristic ridge patterns that permit them to be systematically classified.

8 Chapter 4 Standard Prints on Fingerprint Cards  “Rolling” prints  Ink to first knuckle from edge of nail to edge of nail…rolling motion with arm parallel to surface  Apply with same motion to paper. Cut good one and glue to the proper square.  Should be shaped like a rectangle  NOT an oval 7

9 Chapter 4 Fingerprint Cards  Then ink all fingers at the same time and press flat into proper place on card  Ink thumbs and press flat into proper place on card  You may need help with the rolled prints. Practice first! Kendall/Hunt Publishing Company 8

10 Chapter 4 Kendall/Hunt Publishing Company 9 Arch An arch has friction ridges that enter on one side of the finger and cross to the other side while rising upward in the middle. They do NOT have type lines, deltas, or cores. Types  Plain  Tented

11 Chapter 4 Kendall/Hunt Publishing Company 10 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)

12 Chapter 4 Kendall/Hunt Publishing Company 11 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

13 Chapter 4 Kendall/Hunt Publishing Company 12 Primary Classification The Henry—FBI Classification Each finger is given a point value left right

14 Chapter 4 Kendall/Hunt Publishing Company 13 Primary Classification Assign the number of points for each finger that has a whorl and substitute into the equation: 16 right + 8 right + 4 left + 2 left + 1 left index ring thumb middle little 16 right + 8 righ + 4 right + 2 left + 1 left thumb middle little index ring That number is your primary classification number = +1

15 Chapter 4 Kendall/Hunt Publishing Company 14 Fingerprint Minutiae(details) What would YOU call them?

16 Chapter 4 Kendall/Hunt Publishing Company 15 Fingerprint Minutiae

17 Chapter 4 Kendall/Hunt Publishing Company 16 Ridge Characteristics Minutiae—characteristics of ridge patterns  Ridge ending  Short ridge  Dot or fragment  Bifurcation  Double bifurcation  Trifurcation  Bridge  Island  Enclosure  Spur

18 Chapter 4 Kendall/Hunt Publishing Company 17 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.

19 Chapter 4 Types of Prints  Plastic  Indented or molded, 3D  Made by impressing finger against moldable material to leave an impression  Examples: Paint, putty, soap, fudge, wax  Visible  Left by a finger that has touched a colored material  Examples: Blood, paint, ink  Latent  Essentially invisible to naked eye  Deposits of perspiration, oils, proteins  Must be developed by physical or chemical means Kendall/Hunt Publishing Company 18

20 Chapter 4 Visible  Take a picture!  Plastic: use oblique lighting to highlight features with shadow Kendall/Hunt Publishing Company 19

21 Chapter 4 Kendall/Hunt Publishing Company 20 Latent Prints  Latent fingerprints are those that are not visible to the naked eye. These prints consist of the natural secretions of human skin and require development for them to become visible.  Most secretions come from three glands:  Eccrine—largely water with both inorganic (ammonia, chlorides, metal ions, phosphates) and organic compounds (amino acids, lactic acids, urea, sugars). Most important for fingerprints.  Apocrine—secrete pheromones and other organic materials.  Sebaceous—secrete fatty or greasy substances.

22 Chapter 4 Kendall/Hunt Publishing Company 21 Developing Latent Prints  Developing a print requires substances that interact with secretions that cause the print to stand out against its background. It may be necessary to attempt more than one technique, done in a particular order so as not to destroy the print.  Powders—adhere to both water and fatty deposits. Choose a color to contrast the background.  Iodine—fumes react with oils and fats to produce a temporary yellow brown reaction.

23 Chapter 4 Kendall/Hunt Publishing Company 22 Developing Latent Prints  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. In modern labs and criminal investigations, lasers and alternative light sources are used to view latent fingerprints. These were first used by the FBI in 1978. Since lasers can damage the retina of the eye, special precautions must be taken.

24 Chapter 4 Kendall/Hunt Publishing Company 23 Iodine Fingerprint

25 Chapter 4 Kendall/Hunt Publishing Company 24 Ninhydrin Fingerprint

26 Chapter 4 Kendall/Hunt Publishing Company 25 Cyanoacrylate Fingerprints

27 Chapter 4 Kendall/Hunt Publishing Company 26 Silver Nitrate

28 Chapter 4 Kendall/Hunt Publishing Company 27 Other Prints  Ears—shape, length and width  Foot—size of foot and toes; friction ridges on the foot  Shoes—can be compared and identified by type of shoe, brand, size, year of purchase, and wear pattern  Voice—electronic pulses measured on a spectrograph.

29 Chapter 4 Kendall/Hunt Publishing Company 28 Other Prints Palm—friction ridges can be identified and may be used against suspects.

30 Chapter 4 Kendall/Hunt Publishing Company 29 Other Prints Footprints are taken at birth as a means of identification of infants.

31 Chapter 4 Kendall/Hunt Publishing Company 30 Other Prints Lips—display several common patterns  Short vertical lines  Short horizontal lines  Crosshatching  Branching grooves

32 Chapter 4 Kendall/Hunt Publishing Company 31 Other Prints Teeth—bite marks are unique and can be used to identify suspects. These imprints were placed in gum and could be matched to crime scene evidence.

33 Chapter 4 Kendall/Hunt Publishing Company 32 Other Prints The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.

34 Chapter 4 Kendall/Hunt Publishing Company 33 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

35 Chapter 4 Print ID Algorithm Kendall/Hunt Publishing Company 34

36 Chapter 4 Kendall/Hunt Publishing Company 35 Biometrics  Use of some type of body metrics for the purpose of identification. (The Bertillon system may actually have been the first biometry system.)  Used today in conjunction with AFIS  Examples include retinal or iris patterns, voice recognition, hand geometry  Other functions for biometrics—can be used to control entry or access to computers or other structures; can identify a person for security purposes; can help prevent identity theft or control social services fraud.

37 Chapter 4 Kendall/Hunt Publishing Company 36 More about Prints For additional information about prints and crime, check out Court TV’s Crime Library www.crimelibrary.com/criminal_mind/forensics/fin gerprints/1.html NOVA FORENSICS ON TRIAL...remember Daubert?


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