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Fingerprints

Fingerprints. Lesson 1 – Fingerprints at the Crime Scene. Lesson Essential Questions: How are fingerprints used as evidence in crime scenes?. According to criminal investigators, fingerprints follow 3 fundamental principles:

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Fingerprints

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  1. Fingerprints

  2. Lesson 1 – Fingerprints at the Crime Scene Lesson Essential Questions: • How are fingerprints used as evidence in crime scenes? Kendall/Hunt Publishing Company

  3. According to criminal investigators, fingerprints follow 3 fundamental principles: A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern. A fingerprint pattern will remain unchanged for the life of an individual; however, the print itself may change due to permanent scars and skin diseases. Fingerprints have general characteristic ridge patterns that allow them to be systematically identified.

  4. History from 1850 to 1900 William Herschel—required Indians to put their fingerprints on contracts, and used fingerprints as a means of identifying prisoners Henry Faulds—claimed that fingerprints did not change over time and that they could be classified for identification Alphonse Bertillon—proposed body measurements as a means of identification; termed anthropometry Francis Galton—developed a primary classification scheme based on loops, arches, and whorls Edward Richard Henry—in collaboration with Galton, instituted a numerical classification system Juan Vucetich—developed a fingerprint classification system based on Galton’s that is used in Spanish-speaking countries DactyloscopyThe Study of Fingerprints Kendall/Hunt Publishing Company

  5. Friction ridges (ridges and valleys) are present on the outer layer of our skin that make up our fingerprint. – Not due to genetics. • Outer epidermal layer separated from an inner dermal layer separated by papillae • The papillae form a boundary that determines the friction ridge. Kendall/Hunt Publishing Company

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

  7. Using Fingerprints at a Crime Scene Video Fingerprints inside the Lab Kendall/Hunt Publishing Company

  8. Lesson 2 – Classifying Fingerprints • Essential Questions: • How are fingerprints classified? • What are the basic differences in fingerprints? Kendall/Hunt Publishing Company

  9. All fingerprints can be classified into 3 basic patterns: • Loops • Whorls • Arches 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) Which type of loop is this, if it is on the right hand? Left hand? 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 Kendall/Hunt Publishing Company

  12. 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 Kendall/Hunt Publishing Company

  13. Primary Classification The Henry-FBI Classification System Each finger is given a point value. If your finger has a whorl pattern it is given a number. right left Kendall/Hunt Publishing Company

  14. Using your fingerprint sheet, assign the number of points for each finger that has a whorl and substitute into the equation: Primary Classification, continued right right left left left index ring thumb middle little + 1 = right right right left left thumb middle little index ring + 1 That number is your primary classification number. Kendall/Hunt Publishing Company

  15. Switch cards with others in the class and determine their types of fingerprints and classification numbers. • Fingerprint Factoid: • 60% of people have loops, 35% have whorls, • and 5% have arches Kendall/Hunt Publishing Company

  16. Ridge Classification • You have classified fingerprints according to general patterns. • Ridge Classification uses individual ridge characteristics or minutiae. Kendall/Hunt Publishing Company

  17. The uniqueness of a fingerprint can be determined by the pattern of ridges and valleys as well as the minutiae points, which are points where the ridge structure changes. Did you know? The koala is one of the few mammals (other than primates) that has fingerprints. In fact, koala fingerprints are remarkably similar to human fingerprints; even with an electron microscope, it can be quite difficult to distinguish between the two. • Ridgeology: The study of the uniqueness of friction ridge structures and their use for personal identification.1 1Introduction to Basic Ridgeology by David Ashbaugh, May 1999 Image from http://www.cs.usyd.edu.au/~irena/minutia.gif

  18. Ridge Characteristics Minutiae—characteristics of ridge patterns Kendall/Hunt Publishing Company

  19. Fingerprint Minutiae Kendall/Hunt Publishing Company

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

  21. http://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpghttp://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpg How many ridge characteristics can you identify in this fingerprint?

  22. Lesson 3 – Fingerprinting Techniques: • 1. What techniques are used to compare fingerprints? Kendall/Hunt Publishing Company

  23. Did you know? Camel hair is the most common animal hair used to make fingerprint brushes. Now many brushes (like the one above) are made out of fiberglass. • Latent prints are impressions left by friction ridge skin on a surface, such as a tool handle, glass, door, etc. • Prints may be collected by revealing them with a dusting of black powder and then lifted with a piece of clear tape.

  24. Magnetic powder can also be used to reveal latent prints. This type of powder works better on shiny surfaces or plastic baggies or containers. Some investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces. The cyanoacrylate fuming method (often called the super glue method) is a procedure that is used to develop latent fingerprints on a variety of objects. Ninhydrin is a chemical that bonds with the amino acids in fingerprints and will produce a blue or purple color. It is used to lift prints from surfaces such as paper and cardboard. In modern labs, lasers can be used. Bottom Left: http://www.ok.gov/osbi/images/ninhydrin%20print.jpg

  25. The Automated Fingerprint Identification System—a computer system for storing and retrieving fingerprints Established in the 1970s, AFIS enables law enforcement officials 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 1990s, most large jurisdictions had their own system in place. The problem: A person’s fingerprints may be in one AFIS database 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 AFIS Kendall/Hunt Publishing Company

  26. 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. Biometrics Kendall/Hunt Publishing Company

  27. Iodine Fingerprint Kendall/Hunt Publishing Company

  28. Ninhydrin Fingerprint Kendall/Hunt Publishing Company

  29. Cyanoacrylate Fingerprints Kendall/Hunt Publishing Company

  30. Lips—several common patterns Voice—electronic pulses measured on a spectrograph 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 Other Prints Kendall/Hunt Publishing Company

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

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

  33. Other Prints, continued A man has been convicted of suffocating an eldery woman on the basis of earprint evidence. The assailant was caught after police matched the inprint of his ear on the victim’s window. Police believe that the thief put his ear to the window to listen for signs of anyone home. Earprint catches murderer Kendall/Hunt Publishing Company

  34. Other Prints, continued 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. Kendall/Hunt Publishing Company

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

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

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