1 / 47

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.

bphillips
Download Presentation

Ch. 14 Fingerprints - History

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  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

More Related