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Ch. 14 Fingerprints - History

Ch. 14 Fingerprints - History. I. Hist. of F.P.’s. I. History of Fingerprints. Police have always looked for a foolproof method of human ID. 1 st ID sys . – Bertillon 1883, called . anthropometry. French police expert. A. Early Use of FP’s. Chinese.

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Ch. 14 Fingerprints - History

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  1. Ch. 14 Fingerprints- History

  2. I. Hist. of F.P.’s I. History of Fingerprints • Police have always looked for a foolproof method of human ID. • 1st ID sys. – Bertillon 1883, called . anthropometry French police expert

  3. A. Early Use of FP’s Chinese • : ~1000 B.C. used FP’s to sign legal documents in clay. 2. 1880: Herschel & Fauld suggested that FP’s are useful for ID criminals Offered to create a FP bureau & Scotland Yard said “thanks, but no thanks!” They used Bertillon sys. instead (dumb dumbs) Very few ancient samples today

  4. B. Early Classification of F.P.’s British Gov’t, use FP’s instead… *1892: Galton published Finger Prints 1. Demonstrated no 2 F.P. are identical 2. Showed individual’s F.P. remain unchanged in life 3. Proposed 3 F.P. categories 1. Loops (~60%) 2. Whorls (~30-35%) 3. Arches (~5-10%)

  5. LoopWhorlArch Enters and exits same side of finger at least once, 1 delta At least 2 deltas All lines enter and exit from different sides

  6. C. Two Class. Systems 1. 1891: Dr. Juan Vucetich • Refined over years • Still used in Spanish-speaking countries 2. 1897: Sir Edward Henry (used in most English-speaking countries) • 1901: Dumb dumbs adopted Henry’s sys. • Less than 20 years later

  7. D. Adoption of Fingerprints • 1901: New York City adopted F.P. • 1903: Prison “Twins” – Will West’s -2 criminals w/ same name, appearance, & measurements - ‘s were very different 3. 1904: World’s Fair - U.S. Police trained by Scotland Yard (dumb dumbs)

  8. II. Classification of Fingerprints

  9. A. Fingerprint Vocab • Ridge Characteristics (“minutiae”): Ridge endings, bifurcations, enclosures, & other ridge details • Core: center of the F.P. 3. Delta: triangular area; splits into Y

  10. B. Specific Types of F.P.’s • Two Types of ARCHES 1. Plain Arch: 2. Tented Arch: rolling hill drastic spike

  11. 2 Types of Loops 1. Ulnar Loop 2. Radial Loop Opens towards thumb Opens towards pinky *Must know which hand you are looking at to determine!!

  12. 4 Types of Whorls 2. Central Pocket Loop Whorl: 1.Plain Whorl: line b/w deltas intersects circles line b/w. deltas does not intersect full circles

  13. Practice • Plain whorl or central pocket loop whorl? ANS: Central pocket loop whorl

  14. Practice • Plain whorl or central pocket loop whorl? ANS: Plain whorl

  15. More Whorls 4. Accidental whorl: 3. Double loop whorl: characterized by 3 deltas; frowny face looks like yin yang

  16. More Examples Accidental Whorls: 2 or more types of prints

  17. Practice • Double loop whorl or accidental whorl? ANS: double loop whorl

  18. Practice • Double loop whorl or accidental whorl? ANS: accidental whorl

  19. Radial vs. Ulnar Loops Review

  20. Reclassification of your own F.P.’s

  21. III. F.P. Classification Code • Every print is given a code in the FBI database • Series of letters and numbers 2. Primary Classification is only 1st step 3. Code is based on presence or absence of whorl 4. ~ 25% of the pop. falls into the 1/1 category • only arches or loops • Score of “0” • no whorls • Positive number scores

  22. Primary Classification Coding (Fraction obtained) 1 1 + R. Index R. Thumb L. Thumb R. Little L. Mid. L. Index R. Ring R. Mid. L. Little L. Ring + + + + (16) (4) (8) (2) (1) (1)

  23. PRACTICE!!!!!!!! FP Code Practice

  24. Code Practice #1: • Suspect F.P. 1 1 R2 R4 L1 L3 L5 _ _ _ _ _ _ _ 0 0 0 4 2 0 0 0 0 0 3 5 = R1 R3 R5 L2 L4

  25. #2 • Suspect F.P. _ _ _ _ _ _ _ 0 16 0 0 0 0 9 17 8 0 0 0 1 1 = **NEVER reduce fraction: 2/4 stays as 2/4

  26. #3 We’re going to list all of the numerators first, then all the denominators… 0 16 1 1 16 2 2 0 8 0 0 1 28 =. 19

  27. Find your own Code Cheat Sheet 2 8 1 2 16 8 1 4 16 4

  28. IV. Fundamental Principles of F.P. • First Principle: 1. A F.P. is an individual characteristic 2. fingers with identical prints *Currently 450 million F.P. in FBI database 3. Identification of F.P based on Ridge Characteristics(a.k.a. minutiae) No … yet

  29. e. Bridge • f. Spur (hook) g. Enclosure (eye) h. Crossover Ridge Characteristics a. Ridge ending b. bifurcation (fork) c. short ridge d. ridge island (dot)

  30. B. Second Principle 1. A fingerprint remains unchanged during an individual’s lifetime FUN FACTS a. Fingerprints develop at 3 months gestation. b. Many criminals have tried to alter/eliminate them. - John Dillinger c. Three genetic conditions can prevent fingerprints from forming

  31. 2. Shape of dermal papillae determines form and pattern of ridges Why Do We Have Fingerprints? *Papillae are cells that separate epidermis from dermis.

  32. C. Third Principle *General ridge patterns permit F.P.’s to be systematically classified • Three General patterns (loops, whorls, arches) • loops (~60-65% of population) B. whorls (~30-35%) • arches (~5%) • Individuality of a F.P. is determined notby its general shape, but by a careful study of its ridge characteristics.

  33. Ridge Characteristics Identification - Review

  34. Identify your own minutiae • Take out a pen (blue or black ink) and clear everything else off your desk. • Directions: • Identify 12 different Ridge Characteristics • Must have at least fivediff. R.C.’s out of your 12! • Must have a labeland an “→”

  35. AFIS, F.P. Types, Locating, & Developing

  36. D. AFIS • Automated F.P. ID System • Converts image of F.P. into digital scan • Reference points • ridge endings & bifurcations

  37. AFIS (cont.) FBI 4. has largest database in world • Some cities, counties, states have their own that may or may not link to FBI • Different software config.’s 2 5. Positive match is approx. 8-16 points, but min. req. for court (USA) zero

  38. V. 3 Types of Crime Scene Prints • Visible- seen by naked eye Ex: colored prints left in blood, paint, dust, grease, ink • Plastic- occurs when ridge impressions are left in soft material Ex: wax, soap, putty • Latent (Invisible)- not seen by naked eye • caused by a transfer of oils onto surface “hidden”

  39. VI. Locating Fingerprints • Visible & plastic easy to see • Latent: RUVIS (Reflected UV Imaging Sys.) • UV light reflected off latent oils • UV light is converted into visible light

  40. VII. Methods for Devel. Latent Prints • Super Glue Fuming • Dusting B. Porous Materials (wood, paper) A. Nonporous Materials (glass, metal, plastic) Iodine Fuming Ninhydrin Physical Developer

  41. C. Dusting Powders • Stick to the oils in the fingerprint (physical) • Variety of dust colors/compositions • most common: black, gray, and white

  42. D. Super Glue Fuming • cyanoacrylate in glue reacts w/ proteins & fatty acids in F.P. (chemical) • Creates white print • Must be further developed w/ powder heated fuming cabinet

  43. Developing Latent Prints – Porous Materials

  44. E. Iodine Fuming solid gas • Iodine sublimes at room temp. ( ) • Gaseous iodine sticks to oils in F.P. (physical) • Oldest method • Temporary, fades quickly • Can be fixed by spraying with starch solution • Prints turn blue and last weeks to months

  45. F. Ninhydrin • Choice of most examiners • Reacts w/ amino acids in sweat to produce purple prints (chemical) • Very sensitive The Home Scientist - Ninhydrin • Can develop 15-year-old prints

  46. G. Physical Developer • Most sensitive method • Reacts w/ sweat to form silver-gray print (Chemical) • Destroys print; use as last resort!! • Washes away proteins

  47. VIII. Proper Collection of F.P. • Step 1: Loc. documented, object photographed • Step 2: • Small Object: taken back to lab, F.P. developed, photographed, and lifted • Large Object: F.P. developed, photographed and lifted at crime scene Mythbusters - Fingerprints

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