Fingerprinting

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Fingerprinting

  1. 1. FINGERPRINTING “dermatoglyphics”
  2. 2. History of Fingerprinting <ul><li>1892 – Sir Francis Galton </li></ul><ul><ul><li>published that fingerprints are unique and invariable </li></ul></ul><ul><ul><li>basis for modern fingerprinting science </li></ul></ul><ul><li>1897 – Sir Edward Henry </li></ul><ul><ul><li>introduces the Galton-Henry classification system </li></ul></ul><ul><li>1901 – 1910 widespread use of fingerprints begins </li></ul>
  3. 3. Basics of Fingerprints <ul><li>contact surfaces of hands and feet on humans and some other animals have a series of raised patterns called friction ridges </li></ul><ul><li>identity, number and relative location of ridge characteristics individualize a fingerprint </li></ul>
  4. 4. Basics of Fingerprints <ul><li>friction ridges </li></ul><ul><ul><li>formed before birth between 6 th and 13 th week of development </li></ul></ul><ul><ul><li>contain a single row of pores leading from sweat glands </li></ul></ul><ul><ul><li>if finger is bruised or cut slightly, friction ridges not permanently altered or defaced </li></ul></ul><ul><ul><li>serious injuries may form a permanent scar </li></ul></ul>
  5. 5. Basics of Fingerprints <ul><li>prints are permanent for the life of the individual </li></ul><ul><li>NO TWO PRINTS ARE IDENTICAL </li></ul><ul><ul><li>not even twins </li></ul></ul><ul><ul><li>not even on the same person – you have 10 unique fingerprints </li></ul></ul>
  6. 6. Transmission of Prints <ul><li>when a finger touches a surface, the perspiration and oils from the body are transferred to the surface </li></ul><ul><li>imprints of fingerprints can be left in a soft surface </li></ul><ul><li>a mark can be made by a substance like blood or paint on the finger </li></ul>
  7. 7. Patterns of Friction Ridges <ul><li>three general category patterns with variations among those groups </li></ul><ul><ul><li>arch </li></ul></ul><ul><ul><li>loop </li></ul></ul><ul><ul><li>whorl </li></ul></ul>
  8. 8. Patterns of Friction Ridges <ul><li>arch – no delta(s) </li></ul><ul><ul><li>ridge lines start from one side of the fingertip, rise at the center and exit on the other side of the fingertip </li></ul></ul>
  9. 9. Patterns of Friction Ridges <ul><li>loop – 1 delta </li></ul><ul><ul><li>ridge lines start and end on the same side of the fingertip </li></ul></ul>
  10. 10. Patterns of Friction Ridges <ul><li>whorl – 2 or more deltas </li></ul><ul><ul><li>ridge lines are circles which do not begin or end on either side of the fingertip </li></ul></ul>
  11. 11. arches <ul><li>plain arch – tends to flow across print </li></ul><ul><li>tent arch – significant upthrust in print </li></ul>
  12. 12. loops <ul><li>radial loop – pattern area comes from the thumb side of the hand </li></ul><ul><li>ulnar loop – pattern area comes from the little finger side of the hand </li></ul><ul><li>you must know the hand on which the print comes from to label it radial or ulnar </li></ul>
  13. 13. whorls <ul><li>plain – delta line cuts the inner pattern area </li></ul><ul><li>central pocket – delta line doesn’t cut the inner area </li></ul>
  14. 14. whorls <ul><li>double – contain two core areas (and two deltas) </li></ul><ul><li>accidental – contain more than 2 deltas </li></ul>
  15. 15. Friction Ridge Details - Typica <ul><li>patterns of ridges that differ from one individual to the next are called the ridge details called “typica” or “minutiae” </li></ul><ul><li>experts usually require 10-12 points of similarity in typica to establish that one print matches another </li></ul><ul><li>two main kinds of typica </li></ul><ul><ul><li>ending lines </li></ul></ul><ul><ul><li>bifurcations (splitting lines) </li></ul></ul>
  16. 16. Friction Ridge Details - Typica <ul><li>examples of specific typica </li></ul><ul><ul><li>ending ridge </li></ul></ul><ul><ul><li>bifurcation/fork </li></ul></ul><ul><ul><li>short ridge </li></ul></ul><ul><ul><li>dot </li></ul></ul><ul><ul><li>bridge </li></ul></ul>
  17. 17. Friction Ridge Details - Typica <ul><li>examples of specific typica </li></ul><ul><ul><li>hook/spur </li></ul></ul><ul><ul><li>eye/island/lake </li></ul></ul><ul><ul><li>crossover </li></ul></ul><ul><ul><li>double fork </li></ul></ul><ul><ul><li>triple fork </li></ul></ul>
  18. 18. Friction Ridge Details - Typica
  19. 19. Friction Ridge Details - Typica
  20. 20. Friction Ridge Details - Typica
  21. 21. Identifying a Print <ul><li>make a preliminary match by looking at the general pattern (arch, loop, whorl) </li></ul><ul><li>on the unknown print, identify at least 10 typica </li></ul><ul><li>on the known print, attempt to find all 10 typica in the same relative positions as the ones on the unknown print </li></ul><ul><li>if the typica correspond, the print is an identical match </li></ul>
  22. 22. Making Prints Visible <ul><li>dusting methods </li></ul><ul><ul><li>use powders dusted over a surface </li></ul></ul><ul><ul><li>powder sticks to oils and perspiration that were left on the surface </li></ul></ul><ul><ul><ul><li>light powders on dark surfaces </li></ul></ul></ul><ul><ul><ul><li>dark powders on light </li></ul></ul></ul>
  23. 23. Making Prints Visible <ul><li>developing methods </li></ul><ul><ul><li>use chemicals to make prints visible on surfaces where powder may not work </li></ul></ul><ul><ul><ul><li>nin-hydrin bonds to and colors amino acids left behind – works well on paper </li></ul></ul></ul><ul><ul><ul><li>iodine vapors stick to fingerprint residue on surfaces like unpainted wood </li></ul></ul></ul><ul><ul><ul><li>cyanoacrylate (super glue) vapors adhere to residue on surfaces like styrofoam, metal and plastic </li></ul></ul></ul>
  24. 24. Making Prints Visible <ul><li>developing methods </li></ul><ul><ul><li>use chemicals to make prints visible on surfaces where powder may not work </li></ul></ul><ul><ul><ul><li>fluorescence techniques </li></ul></ul></ul>
  25. 25. Collecting and Saving Prints <ul><li>dusted and developed prints should be photographed immediately </li></ul><ul><li>most prints can be “lifted” with adhesive tape or ready made adhesive sheets to preserve them </li></ul><ul><li>photographed or lifted prints can later be scanned into IAFIS </li></ul>
  26. 26. Fingerprint Data Banks <ul><li>1924 – FBI Identification Division created and 750,000 prints were transferred there </li></ul><ul><li>currently FBI possesses over 250 million sets of prints </li></ul><ul><ul><li>criminal prints –from individuals arrested or convicted of a crime </li></ul></ul><ul><ul><li>civil prints – from government employees and applicants for federal jobs </li></ul></ul>
  27. 27. Fingerprint Data Banks <ul><li>digital system has replaced the traditional fingerprint card </li></ul><ul><li>called IAFIS – Integrated Automated Fingerprint Identification System </li></ul><ul><li>allows officers anywhere to take suspect’s prints on electronic pad or scan a lifted print in order to make a comparison </li></ul>

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