Friction Ridges and Fingerprints

1. Friction Ridges and Fingerprints

2. No two people have the same fingerprints • Not even identical twins • Demonstrates that fingerprints are the result of both heredity and environment

3. Forensic Fingerprints… history • Cesare Lombroso - Theory of l’umo delinquente - late 1800’s • or The Criminal Man • Criminals are evolutionary throwbacks to primates

4. Lombroso said that criminals have certain physical traits • Does that mean that some people are “Natural Born Killers”? • Lombroso thought so

5. Hence the need for more measurable ways to catch a criminal • Alphonse Bertillion - 1883- developed Bertillion Method - a complex system of body measurements • Anthropometric – Body measurements

6. First known use of Fingerprints in the United States • 1902- City of New York, used fingerprints on exams to prevent more well-educated persons from taking a civil service exam for the New York Civil Service Commission

7. First Homicide Conviction as a result of Fingerprint evidence • 1911 - Thomas Jennings was convicted of murder during a burglary in Chicago

8. International Association for Identification • Formed in 1915 - originally intended as a professional association for Bertillion Clerks • Changed to focus on fingerprints

9. 1921 - Identification Division of the FBI • Now the largest Identification Library in the world, housing more than 55 million criminal prints and histories

10. Anatomy of Friction Ridges • Appear on the palms, soles of feet and ends of fingers and toes • Are unique for the individual • Form in the 9th or 10th week of Fetal developement

11. All Primates have Friction Ridges

12. Friction Ridges enable us to grasp objects - • Primates also have nails instead of claws…claws would get in the way of holding onto objects

13. There are two main layers of our skin

14. Epidermis is made up of mostly dead skin cells - 5 layers to epidermis…only Stratum basale is alive and dividing

17. At 14 weeks sweat glands and ducts form in utero, and form our Primary Friction Ridges

19. The interface between the dermis and the epidermis form secondary Friction Ridges

20. In looking at this image, Do friction ridges form from the dermal layer or the epidermal layer?

22. Friction Ridges or Fingerprints can be classified as Patent or Latent • Patent if they are visible to the unaided eye - these appear when some material is present on the Friction Ridges and makes the print visible • Examples: • Oily hand on clear glass, blood or paint on fingers can also cause Patent prints

23. Latent Prints • These require some assistance to make visible • Latent Prints are composed of the sweat or body oils that are transferred from the ridge pattern to some substrate

24. Fingerprint Persistence > Fingerprints stick around for a long time > On porous surfaces, paper, wood or cardboard, can last up to 40 years!!!! -as long as they aren’t exposed to water • On non-porous (metal, plastic etc.) surfaces can last even longer!

25. Fingerprint classification • Friction Ridges form one of three basic patterns on each finger

26. Arches • Loops • Whorls

27. The Arch - Plain Arch

28. Tented Arch

29. Loops - 60-70% of finger prints are loops

30. Whorls 25-30% of prints

31. Radial Loop

32. Double Looped Whorl

33. Double Looped Whorl • Two separate, distinct loop formations

34. Central Pocket Whorl

35. Any print with more than two deltas is an Accidental Whorl • A Delta is a triangle

36. Composites include patterns in which combinations of the tented arch, loop and whorl are found in the same print, also patterns where the majority of ridges are loops and a few ridges at the centre or side are whorls. These are subdivided into central pocket loops, double loops and accidentals.

37. Central pocket loop.Central pocked loops are differentiated from whorls by placing the line of the glass across the two delta points. This line must not touch or cross any ridge formation within the inner area of aul pattern. (The inner pattern is that portion of the print contained inside both deltas.)

38. Double Loop • Double loop patterns consist of two separate loop formations, with two separate and distinct sets of staples and two deltas. They include the lateral pocket loop and twinned loop types.

39. Primary Characteristics Recognized by the FBI: • Plain Arch • Tented Arch • Ulnar Loop • Radial Loop • Double loop (classified as a whorl) • Whorl • Central Pocket Whorl • Accidentals (usually classified as a whorl)

40. 1880 Dr Henry Faulds wrote to Charles Darwin asking for help in a fingerprint identification system • Sir Frances Galton - 1892“Finger Prints”

41. Juan Vucetich Inspired by Galton’s book Made first positive identification based on fingerprint - Francesca Rojas

42. Sir Edward Henry • Was influenced by Galton’s book • 1896 - developed the Henry Classification System

43. Henry Classification System • Primary Characteristics are a ssigned values • Primary characteristics; Arches, Loops, Whorls • Values come in the form of fractions • I.e. 1/13 or 23/2 - never reduced!!!

44. Each finger is assigned a value • If a Whorl is present the value is inputed • If No whorl is present a zero is put into the equation • Ri/rt + rr/rm + lt/rl + lm/li + ll/lr + 1/1 =16 =8 =4 =2 =1

45. The Henry System can be used for Loops and Arches as well

46. The Henry System should NEVER be used to identify a person • It is only used to rule out suspects

47. The FBI uses the NCIC FPC system for identification • Like the Henry system it cannot be a positive identifier • Used to rule out suspects

48. Old FBI systems had problems transmitting Henry numbers • The NCIC FPC system was easier to transmit - no fractions

49. NCIC FPC • Number is a 20 digit alpha-numeric number • Two characters are used for each finger • Begins with right thumb as number 1 • Left thumb is number 6… • Left little is number 10

50. Which method is better? • FBI holds a little more information than the Henry System • Number of ridges on each loop • What type of whorl, or loop