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  1. 1. Chapter 14 Fingerprints
  2. 2. History <ul><li>Alphonse Bertillion </li></ul><ul><ul><li>French police expert </li></ul></ul><ul><ul><li>First systematic attempt at personal identification was </li></ul></ul><ul><li>Bertillion system </li></ul><ul><ul><li>Relied on a detailed description of the subject </li></ul></ul><ul><ul><li>Combined with full length and profile photographs </li></ul></ul><ul><ul><li>System of precise body measurements called anthropometry </li></ul></ul>FINGERPRINTS
  3. 3. History <ul><li>Francis Galton </li></ul><ul><ul><li>1892 </li></ul></ul><ul><ul><li>Classic textbook finger prints </li></ul></ul><ul><li>At Galton’s insistence </li></ul><ul><ul><li>British government adopted fingerprinting </li></ul></ul><ul><ul><li>Supplement to the bertillion system. </li></ul></ul><ul><li>Next step </li></ul><ul><ul><li>Creation of classification systems </li></ul></ul><ul><ul><li>Capable of filing many thousands of prints </li></ul></ul><ul><ul><li>Logical and searchable sequence. </li></ul></ul>FINGERPRINTS
  4. 4. History <ul><li>Dr Juan Vucetich </li></ul><ul><ul><li>Devised a classification system </li></ul></ul><ul><ul><li>Still used in most spanish-speaking countries </li></ul></ul><ul><li>Sir Edward Henry: system used in most English-speaking countries. </li></ul><ul><li>Will West and William West case </li></ul><ul><ul><li>1903 </li></ul></ul><ul><ul><li>Bertillion system could not distinguish between men </li></ul></ul><ul><ul><li>Fingerprinting that clearly distinguished them </li></ul></ul>FINGERPRINTS
  5. 5. History <ul><li>Fingerprinting used by the New York city civil service commission in 1901 </li></ul><ul><li>Training of American police by Scotland yard representatives at the 1904 world’s fair </li></ul>FINGERPRINTS
  6. 6. Fingerprint Principles Reproduction of friction skin ridges Palm side of the fingers & thumbs FINGERPRINTS
  7. 7. Fingerprint Principles <ul><li>Individual characteristic </li></ul><ul><ul><li>Because no two fingers with with identical ridge characteristics </li></ul></ul><ul><li>Remains unchanged during an individual’s lifetime </li></ul><ul><li>General ridge patterns that permit systematic classification </li></ul>FINGERPRINTS
  8. 8. Principle One Individual Characteristic No Fingers Identical
  9. 9. Principle One <ul><li>Mathematical probability for existence of two identical fingerprint patterns in the world’s population = almost zero </li></ul><ul><li>Millions upon millions of individuals who have had their prints classified </li></ul><ul><ul><li>No two fingerprints have been found to be identical </li></ul></ul>FINGERPRINTS
  10. 10. Figure 14–1  Fingerprint ridge characteristics. Courtesy Sirchie Finger Print Laboratories, Inc., Youngsville, N.C.,
  11. 11. Principle One <ul><li>Individuality of fingerprint not determined by its general shape or pattern </li></ul><ul><li>Careful study of its ridge characteristics, known as minutiae. </li></ul><ul><ul><li>Identity, number, and relative location </li></ul></ul><ul><ul><li>Individuality to a fingerprint. </li></ul></ul><ul><li>As many as 150 minutiae on the average finger </li></ul>FINGERPRINTS
  12. 12. Principle One <ul><li>Three year study </li></ul><ul><ul><li>“ No valid basis exists for requiring a predetermined minimum number of friction ridge characters which must be present in two impressions in order to establish positive identification” </li></ul></ul><ul><li>Judicial proceeding </li></ul><ul><ul><li>Expert must demonstrate a point-by-point comparison </li></ul></ul><ul><ul><li>To prove the identity of an individual </li></ul></ul>FINGERPRINTS
  13. 13. Fingerprint Comparison Figure 14–2  A fingerprint exhibit illustrating the matching ridge characteristics between the crime-scene print and an inked impression of one of the suspect’s fingers. Courtesy New Jersey State Police.
  14. 14. Principal Two Remains Unchanged During Lifetime
  15. 15. Principal Two <ul><li>Epidermis </li></ul><ul><ul><li>Outer layer of the skin </li></ul></ul><ul><li>Dermis </li></ul><ul><ul><li>Inner layer of the skin </li></ul></ul><ul><li>Dermal papillae </li></ul><ul><ul><li>Layer of cells between the epidermis and dermis </li></ul></ul><ul><ul><li>Responsible for determining the form and pattern of the ridges on the surface of the skin </li></ul></ul>
  16. 16. Principal Two <ul><li>Dermal papillae develop in the human fetus </li></ul><ul><li>Ridge patterns will remain unchanged throughout life </li></ul><ul><li>Enlarge during growth </li></ul><ul><li>Fingerprint remains unchanged during lifetime </li></ul>
  17. 17. Principle Two <ul><li>Skin ridge is populated with pores leading to sweat glands </li></ul><ul><li>Perspiration is deposited on the skin </li></ul>FINGERPRINTS
  18. 18. Principle Two <ul><li>Finger touches a surface </li></ul><ul><ul><li>Perspiration </li></ul></ul><ul><ul><li>Oils from hairy portions of the body </li></ul></ul><ul><ul><li>Transferred onto surface </li></ul></ul><ul><li>Leaves fingerprint </li></ul>FINGERPRINTS
  19. 19. Principle Three Ridge Patterns Permit Systematic Classification
  20. 20. Principle Three <ul><li>All fingerprints </li></ul><ul><ul><li>divided into three classes </li></ul></ul><ul><ul><li>Loops </li></ul></ul><ul><ul><li>Arches </li></ul></ul><ul><ul><li>whorls </li></ul></ul><ul><ul><li>L.A.W. </li></ul></ul>FINGERPRINTS
  21. 21. Loop Patterns
  22. 22. Principle Three - Loops <ul><li>A loop must have one or more ridges entering from one side of the print, recurving, and exiting from the same side. </li></ul><ul><ul><li>If the loop opens toward the little finger, it is called an ulnar loop. </li></ul></ul><ul><ul><li>If the loop opens toward the thumb, it is called a radial loop. </li></ul></ul>
  23. 23. Principle Three - Loops Figure 14–5  Loop pattern.
  24. 24. Principle Three - Loops <ul><li>Must have one delta </li></ul><ul><li>Ridge point at or directly in front of the point where two ridge lines (type lines) diverge </li></ul>FINGERPRINTS
  25. 25. Whorls
  26. 26. Principle Three- Whorls <ul><li>Divided into four groups </li></ul><ul><ul><li>Plain </li></ul></ul><ul><ul><li>Central pocket loop </li></ul></ul><ul><ul><li>Double loop </li></ul></ul><ul><ul><li>Accidental </li></ul></ul><ul><li>All have type lines and minimum of two deltas </li></ul>FINGERPRINTS
  27. 27. Whorls <ul><li>Plain whorl and central pocket loop have at least one ridge that makes a complete circuit </li></ul><ul><li>Double loop: two loops combined into one fingerprint </li></ul><ul><li>Accidental </li></ul><ul><ul><li>Two or more patterns </li></ul></ul><ul><ul><li>Or pattern not covered by the other categories </li></ul></ul>FINGERPRINTS
  28. 28. Plain Whorls <ul><li>More than 1 valid delta </li></ul><ul><li>If you look at image A  you should be able to identify the two delta's. If not then look at image B and you will see that they are displayed in the red boxes. </li></ul><ul><li>Whorl: one or more ridges which make complete circuit </li></ul><ul><li>Two delta's </li></ul><ul><ul><li>Between which an imaginary line is drawn </li></ul></ul><ul><ul><li>At least one recurving ridge within the inner pattern area cut or touched.  </li></ul></ul>
  29. 29. Plain Whorls
  30. 30. Whorls <ul><li>Inner area of the pattern forms circle or oval </li></ul><ul><li>Specific ridges that are making or trying to make the circle </li></ul><ul><ul><li>Imaginary line between the two delta's (the red line in image) </li></ul></ul><ul><ul><li>No lines that form the circle are intersected </li></ul></ul>
  31. 31. Whorls
  32. 32. Arches
  33. 33. Principle Three - Arches <ul><li>Least common of general patterns </li></ul><ul><ul><li>Plain arches </li></ul></ul><ul><ul><li>Tented arches </li></ul></ul><ul><li>No lines that form the circle are intersected </li></ul>FINGERPRINTS
  34. 34. Plain Arches <ul><li>Ridges entering from one side of the print </li></ul><ul><li>Rising and falling </li></ul><ul><li>Exiting on the opposite side </li></ul><ul><li>Like a wave </li></ul>
  35. 35. Tented Arches <ul><li>Sharp upthrust or spike </li></ul><ul><li>The ridges meet at an angle that is less than 90 degrees </li></ul><ul><li>Arches do not have type lines, deltas, or cores </li></ul>FINGERPRINTS
  36. 36. Primary Classification <ul><li>Based on knowledge of fingerprint pattern classes </li></ul><ul><li>Fingers are paired up </li></ul><ul><ul><li>One finger in the numerator of a fraction </li></ul></ul><ul><ul><li>Other in the denominator </li></ul></ul><ul><li>Presence or absence of the whorl pattern </li></ul><ul><ul><li>Basis for the determination of the primary classification </li></ul></ul>FINGERPRINTS
  37. 37. Primary Classification <ul><li>Whorl pattern </li></ul><ul><ul><li>Any finger of the first pair value = 16 </li></ul></ul><ul><ul><li>On the second pair value = 8 </li></ul></ul><ul><ul><li>On the third pair value = 4 </li></ul></ul><ul><ul><li>On the second pair value = 2 </li></ul></ul><ul><ul><li>On the last pair value = 1 </li></ul></ul><ul><li>Any finger having a loop or arch value = 0 </li></ul>FINGERPRINTS
  38. 38. Primary Classification <ul><li>Values for all 10 fingers totaled </li></ul><ul><li>1 is added to both the numerator and denominator </li></ul><ul><li>Fraction obtained is primary classification. </li></ul>FINGERPRINTS
  39. 39. Primary Classification <ul><li>25 percent of the population </li></ul><ul><ul><li>1/1 category </li></ul></ul><ul><ul><li>All fingers loops or arches </li></ul></ul><ul><li>Cannot in itself unequivocally identify an individual </li></ul><ul><li>Provides the fingerprint examiner with a number of candidates </li></ul>
  40. 40. AFIS
  41. 41. AFIS <ul><li>Computer to scans, digitally encodes fingerprints </li></ul><ul><li>Can be high-speed computer processed </li></ul>FINGERPRINTS
  42. 42. AFIS <ul><li>AFIS aids in classifying and retrieving fingerprints </li></ul><ul><ul><li>Converts image of a fingerprint into digital minutiae </li></ul></ul><ul><ul><li>Contain data showing ridges at their points of termination (ridge endings) and their branching into two ridges (bifurcations). </li></ul></ul><ul><li>Thousands of comparisons per second </li></ul><ul><li>Produces a list of file prints to be examined by a trained fingerprint expert </li></ul>FINGERPRINTS
  43. 43. Visible & Latent Prints
  44. 44. Latent Prints <ul><li>Invisible fingerprints </li></ul><ul><li>Finger touches a surface </li></ul><ul><li>Body perspiration and/or oils present </li></ul><ul><li>Transferred to that surface </li></ul><ul><li>Leaves impression </li></ul><ul><li>Invisible to the eye </li></ul>FINGERPRINTS
  45. 45. Visible Prints <ul><li>Fingers touch a surface after contact with a colored material such as blood, paint, grease, or ink </li></ul><ul><li>Plastic prints: left on a soft material, such as putty, wax, soap, or dust </li></ul><ul><li>Little problem to the investigator </li></ul><ul><li>Usually distinct and visible to the eye. </li></ul>FINGERPRINTS
  46. 46. Detecting Prints
  47. 47. Detecting Prints <ul><li>Hard nonabsorbent surfaces </li></ul><ul><ul><li>Glass, mirror, tile, painted wood </li></ul></ul><ul><ul><li>Developed by the application of a powder </li></ul></ul><ul><li>Porous surfaces </li></ul><ul><ul><li>Papers, cardboard, and cloth </li></ul></ul><ul><ul><li>Require treatment with a chemical </li></ul></ul>FINGERPRINTS
  48. 48. Ninhydrin <ul><li>Reacts chemically with trace amounts of amino acids </li></ul><ul><li>Produces a purple-blue color </li></ul><ul><li>Messy and stains skin badly </li></ul>
  49. 49. Physical Developer <ul><li>Silver nitrate-based reagent </li></ul><ul><li>Used when other chemical methods are ineffective </li></ul><ul><li>Silver nitrate solution stain skin </li></ul>
  50. 50. Super Glue ® <ul><li>Nonporous surfaces </li></ul><ul><ul><li>Metals, electrical tape, leather, plastic bags </li></ul></ul><ul><ul><li>Fumes from the glue adhere to the print </li></ul></ul><ul><ul><li>Produce white latent print </li></ul></ul><ul><li>98 to 99 percent cyanoacrylate ester </li></ul><ul><li>Super Glue fuming </li></ul><ul><ul><li>Fuming chamber (for up to six hours) </li></ul></ul><ul><ul><li>Handheld wand that heats a small cartridge containing cyanoacrylate </li></ul></ul>FINGERPRINTS
  51. 51. Reflected UV Imaging System <ul><li>RUlVIS </li></ul><ul><li>No chemicals or powder </li></ul><ul><li>Locate With light source </li></ul><ul><li>investigator develops the print in the most appropriate fashion </li></ul>FINGERPRINTS
  52. 52. Figure 14–17  Schematic depicting latent-print detection with the aid of a laser. A fingerprint examiner, wearing safety goggles containing optical filters, examines the specimen being exposed to the laser light. The filter absorbs the laser light and permits the wavelengths at which latent-print residues fluoresce to pass through to the eyes of the wearer. Courtesy Federal Bureau of Investigation, Washington, D.C.
  53. 53. Powders <ul><li>Powders, available in a variety of colors, can be applied with a brush or magnetic wand, and adhere to perspiration and/or body oils of the print. </li></ul>
  54. 54. Iodine Fuming <ul><li>Molecular iodine solid at room temperature </li></ul><ul><li>Heat iodine crystals </li></ul><ul><li>Iodine vapors </li></ul><ul><li>Combine with latent prints to make them visible </li></ul><ul><ul><li>Iodine prints are not permanent </li></ul></ul><ul><ul><li>Will fade </li></ul></ul><ul><ul><li>Must photograph the prints immediately </li></ul></ul>
  55. 55. Fluorescence <ul><li>High sensitivity </li></ul><ul><li>New chemical techniques used to visualize latent fingerprints </li></ul><ul><li>Fingerprints treated with chemicals </li></ul><ul><ul><li>Induce fluorescence when exposed to lasers </li></ul></ul><ul><ul><li>High-intensity light sources (“alternate light sources”) </li></ul></ul><ul><ul><li>Quartz halogen, xenon arc, or indium arc light sources. </li></ul></ul>FINGERPRINTS
  56. 56. Preservation of Prints <ul><li>Visualized latent print </li></ul><ul><li>Permanently preserved </li></ul><ul><ul><li>Future comparison </li></ul></ul><ul><ul><li>Possible use as court evidence </li></ul></ul><ul><li>Photograph must be taken </li></ul><ul><ul><li>Before any attempts at preservation </li></ul></ul>
  57. 57. Transporting Prints <ul><li>small object: preserve in its entirety. </li></ul><ul><li>large immovable objects </li></ul><ul><ul><li>developed with a powder </li></ul></ul><ul><ul><li>“ lift” with a broad adhesive tape. </li></ul></ul><ul><ul><li>tape placed on properly labeled card </li></ul></ul><ul><ul><li>good background contrast with the powder </li></ul></ul>FINGERPRINTS
  58. 58. Digital Imaging <ul><li>Picture converted into digital computer file </li></ul><ul><li>Help of digital imaging software </li></ul><ul><ul><li>Enhanced for the most accurate and comprehensive analysis </li></ul></ul><ul><li>Compare function </li></ul><ul><ul><li>Two images side by side </li></ul></ul><ul><ul><li>Allows the examiner to chart the common features on both images simultaneously </li></ul></ul>FINGERPRINTS
  59. 59. Fingerprint Patterns
  60. 60. Taking Fingerprints
  61. 61. Summary
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