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Ch 8 fingerprints


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  • Alphonse Bertillon: Anthropometry/Father of criminal identification. In 1892 Francis Galton published his classic textbook Finger Prints . At Galton’s insistence, the British government adopted fingerprinting as a supplement to the Bertillon system. The next step was the creation of classification systems capable of filing many thousands of prints in a logical and searchable sequence.
  • 1850’s: Prisons began photographing inmates for ID purposes. 1880’s: Gained popularity after Kodak camera developed. Allan Pinkerton: Detective Agency-Rogues Gallery. NYPD Detective Thomas Byrnes: Developed NYPD gallery. “ mug” shots
  • In 1903, Will West/William West incident. Fingerprinting clearly distinguished them. After the Will West incident NY Civil Service began fingerprinting applicants (1901). 1904 World’s Fair: Scotland Yard introduces fingerprinting to US Police Forces
  • Fingerprints: Reproduction of friction skin ridges found on the palm side of the fingers and thumbs. The basic principles: 1. Uniqueness: individual characteristic; no two fingers possess identical ridge characteristics 2. Permanence: fingerprints remain unchanged 3. Patterns: general ridge patterns that permit them to be systematically classified.
  • Mathematically, the probability for the existence of two identical fingerprint patterns in the world’s population is extremely small. Besides theoretical calculations, of the millions upon millions of individuals who have had their prints classified, no two fingerprints have been found to be identical. The individuality of a fingerprint is not determined by its general shape or pattern, but by the careful study of its ridge characteristics, known as minutiae. It is the identity, number, and relative location of these minutiae that imparts individuality to a fingerprint. There are as many as 150 minutiae on the average finger.
  • Points? How many required for ID in US Courts? After a three year study, it was determined that “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.” Sufficient number of friction ridge details present for conclusion 100%
  • Conclusions: -Subject made the print -Subject could not have made the print -Print had insufficient detail to be evaluated In a judicial proceeding, an expert must demonstrate a point-by-point comparison in order to prove the identity of an individual.
  • Epidermis: outer layer of the skin Dermis: inner layer of the skin. Dermal papillae: layer of cells between the epidermis and dermis/determines form and pattern of the ridges on the surface of the skin. Develops in the fetus and remains unchanged throughout life. Each skin ridge is populated with pores leading to sweat glands from which perspiration is deposited on the skin. Once the finger touches a surface, perspiration, along with oils that may have been picked up by touching the hairy portions of the body, is transferred onto that surface, leaving the finger’s ridge pattern (a fingerprint).
  • ARCHES: Least common type of pattern Only 5% of all patterns 2 subcategories: a. Plain b. Tented
  • Latent prints deposited on hard and nonabsorbent surfaces (e.g., glass, mirror, tile, and painted wood) are preferably developed by the application of a powder; whereas prints on porous surfaces (e.g., papers, cardboard, and cloth) generally require treatment with a chemical. Examiners use various chemical methods to visualize latent prints on porous surfaces, such as iodine fuming, ninhydrin, and Physical Developer. Super Glue ® fuming develops latent prints on nonporous surfaces, such as metals, electrical tape, leather, and plastic bags. Development occurs when fumes from the glue adhere to the print, usually producing a white latent print
  • A devise called the Reflected Ultraviolet Imaging System (RUVIS) can aid in the detecting of latent fingerprints, without chemicals or powder. Once located, the crime scene investigator can develop the print in the most appropriate fashion. 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. Iodine fuming involves heating iodine crystals that cause vapors which combine with latent prints to make them visible. Iodine prints are not permanent and will fade, making it necessary to photograph the prints immediately.
  • Ninhydrin reacts chemically with trace amounts of amino acids present in latent prints to produce a purple-blue color. Physical Developer is a silver nitrate-based reagent used to develop prints when other chemical methods are ineffective. Super Glue ® is approximately 98 to 99 percent cyanoacrylate ester, a chemical that actually interacts with and visualizes a latent fingerprint. Super Glue fuming can be accomplished by using either a fuming chamber (for up to six hours) or a handheld wand that heats a small cartridge containing cyanoacrylate.
  • The high sensitivity of fluorescence serves as the underlying principle of many of the new chemical techniques used to visualize latent fingerprints. Fingerprints are treated with chemicals that would induce fluorescence when exposed to lasers, or high-intensity light sources (“alternate light sources”) such as quartz halogen, xenon arc, or indium arc light sources. Once the latent print has been visualized, it must be permanently preserved for future comparison and for possible use as court evidence. A photograph must be taken before any further attempts at preservation are made.
  • If the object is small enough to be transported without destroying the print, it should be preserved in its entirety. Prints on large immovable objects that have been developed with a powder can best be preserved by “lifting” with a broad adhesive tape. Then, the tape is placed on a properly labeled card that provides a good background contrast with the powder.
  • Digital imaging is the process by which a picture is converted into a digital computer file. With the help of digital imaging software, fingerprints, which are often not in perfect condition, can now be enhanced for the most accurate and comprehensive analysis. An important and useful tool, especially for fingerprint identification, is the compare function that places two images side by side and allows the examiner to chart the common features on both images simultaneously.
  • The heart of AFIS technology is the ability of a computer to scan and digitally encode fingerprints so that they can be subject to high-speed computer processing. 1999 by FBI AFIS aids in classifying and retrieving fingerprints by converting the image of a fingerprint into digital minutiae that contain data showing ridges at their points of termination (ridge endings) and their branching into two ridges (bifurcations). When the search is complete (a computer can make thousands of comparisons per second), the computer produces a list of file prints that must be examined by a trained fingerprint expert.
  • Transcript

    • 1. Chapter 8Fingerprints
    • 2. History Alphonse Bertillon: anthropometry 1892 Francis Galton-Finger Prints-UK-fingerprinting -supplement to Bertillon system
    • 3. History 1850’s:-photographing inmates Allan Pinkerton:-rogues gallery NYPD Detective Thomas Byrnes:-NYPD gallery-“mug” shots
    • 4. Mug shots NYPD: original collection of mug shots
    • 5. History Will West/William West (1903)-2 inmates/same anthropometrical measurements-fingerprints ID’d them 1904 World’s Fair:-fingerprinting introduced to US Police
    • 6. Mug shots Collection of mug shots
    • 7. Mug Shots John Dillinger
    • 8. Mug Shots Alphonse Capone
    • 9. Mug Shots James Brown
    • 10. Mug Shots Nick Nolte
    • 11. FingerprintsWhat are fingerprints? Friction ridge skin pattern ridges (hills)/furrows (valleys) Black = Ridges White = Valleys
    • 12. FingerprintsWhat are fingerprints? embryonic development genetics, detail-random
    • 13. Fingerprints3 types1. Visible – dirt/grease/blood
    • 14. Fingerprints3 types2. Impression – soft material (butter, putty, tar)
    • 15. Fingerprints3 types3. Latent – requires processing
    • 16. Fingerprints > Analysisinvisible components-sweat glands secrete onto fingers/palms-Sweat contains:  Inorganic ions (Na+, Cl -)  Lipids  Proteins, amino acids  Other
    • 17. Visible prints
    • 18. Fingerprint Principles 3 principles:1. Uniqueness:2. Permanence:3. Patterns:
    • 19. Principle One UNIQUENESS:-no two people identical-identification-ridge characteristics (minutiae)-> 150 minutiae on average finger
    • 20. Principle One DO NOT WRITE DOWN! Points? How many required for ID in US Courts?-“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”-sufficient number of friction ridge details present for conclusion 100%
    • 21. Principle One Conclusions: Match no match inconclusive
    • 22. Principle Two PERMANENCE: Epidermis-outer layer Dermis-inner layer Form in womb/unchanged for life
    • 23. PRINCIPLE THREE Patterns:-classification/filing-3 patternsDO NOT CONFUSE PATTERNS WITH PRINCIPLES!!!
    • 24. Principle ThreePattern 1:Loop:-60 %
    • 25. Principle ThreePattern 2:Whorls:35%
    • 26. WhorlsDouble Loop Whorl Accidental Whorl
    • 27. Principle Three ARCHES: Least common 5% a. Plain b. Tented
    • 28. Arches Plain  Tented
    • 29. Developing Prints Surface=substrate Hard/nonabsorbent: powder Porous: chemical
    • 30. Detecting Prints Powders:-adhere to perspiration/body oils Iodine fuming:-iodine crystals release vapors
    • 31. Detecting Prints Ninhydrin:-amino acids/purple-blue Super Glue®:- cyanoacrylate ester
    • 32. Developing Prints Fluorescence:-chemicals-fluorescence -high-intensity light-photographs must be taken before attempts at lifting
    • 33. Fingerprints > AnalysisPhysical Development: Dusting Powder adheres Brush and Powder
    • 34. Fingerprints > AnalysisPhysical Development: Dusting Magnetic Brush and Powder
    • 35. Powder Latent print developed with powder
    • 36. Powder  Print in dust: Left-actual print Middle-developed with powder Right-photographed
    • 37. Powder  Shell casing
    • 38. Fingerprints > AnalysisChemical Development:2. Iodine Fuming  Iodine reacts w/ lipid components  Fuming wand/chamber Dirty Brown Color
    • 39. Fingerprints > AnalysisChemical Development:3. Ninhydrin  Reacts with amino acids; purple color  Painted or sprayed on area  Heated to react
    • 40. Development Fingerprints on the inside of a rubber glove
    • 41. Development Fingerprints developed on plastic bag
    • 42. Development Inside of rubber gloves treated with ninhydrin
    • 43. Development  Ninhydrin
    • 44. Development  Ninhydrin-Note initials at top-CHAIN OF CUSTODY
    • 45. Development Super glue developed prints
    • 46. Developing Latent prints visulaized using fluorescent powder
    • 47. Developing Different colored fluorescent powder
    • 48. Development and Collection Scene or Lab? Small objects:-preserved/transported Large immovable objects:-develop prints/lift
    • 49. Digital Imaging Digital imaging:-picture converted-digital computer file Compare function:-images side by side
    • 50. Fingerprints > CollectionCollection of prints:Sometimes a photograph will be the only permanent record.
    • 51. Fingerprint Kit
    • 52. FingerprintsHow are fingerprints analyzed? Categorized by pattern and minutiae
    • 53. FingerprintsHow are fingerprints analyzed?Patterns Loop Whorl Arch
    • 54. FingerprintsHow are fingerprints analyzed?Minutiae Bifurcation Ridge Ending Dot Island
    • 55. AFIS Computer scans/digitally encode fingerprints-classifying /retrieving-digital minutiae-list of file prints-examined by expert
    • 56. Old system of fingerprints
    • 57. Fingerprints Computer software compares the location of these minutiae.
    • 58. AFIS AFIS highlights all the identifiable minutia.
    • 59. Madrid Bombing Timeline March 11, 2004 – Terrorists bomb several trains in Madrid, Spain March 13, 2004 – LPU receives electronic transmission of digital images (no info, scale, etc.)  8 latent prints  Known exemplars March 19, 2004
    • 60. Madrid April 13, 2004 – Spanish National Police (SNP) issues ‘negativo’ report regarding latent print April 21, 2004 – LPU rep travels to Spain to provide basis of identification to SNP
    • 61. Madrid May 6, 2004 – Brandon Mayfield arrested by FBI Portland May 19, 2004 (in California) – Defense expert verifies FBI identification May 19, 2004 – SNP informs FBI they have identified the latent fingerprint with another individual May 20, 2004 – Judge releases Mayfield