1. Chapter 14 Fingerprints

2. Background Info. Bertillon’s system of anthropometry was the 1 st criminal identification method It was used for 20 years, but the Will West situation proved it to be inaccurate Chinese used fingerprints to sign documents 3,000 years ago!!

3. Important People

4. Henry Fauld (1880) Said that skin ridge patterns could be used to identify criminals He was ignored

5. Francis Galton (1892) Published Finger Prints (1 st book on the topic) 3 Patterns:  Loops  Whorls  Arches

6. Sir Edward Henry (1897) Developed the classification system used today

7. The 3 Principles of Fingerprints

8. 1. A fingerprint is an individual characteristic  no two have identical ridge characteristics **Ridge Characteristics (minutiae)**  Endings  Enclosures  Bifurcations (branching)

10. 2. Fingerprints remain unchanged during a lifetime  Dermal papillae determine the form & pattern  Develop in the fetus & never change except to grow

12.  Gangster  used acid to destroy his prints  unsuccessful **John Dillinger**

14. 3. Fingerprints have ridge patterns that are classified by: Loops  60-65% Whorls  30-35% Arches  5%

15. Types of Ridge Patterns

16. 1. Loops Ridge patterns that enter & exit on the same side of the finger A. Ulnar Loop  loop comes from the little finger B. Radial Loop  comes from the thumb

17. 2. Whorls Ridge patterns that are somewhat circular in nature A. Plain Whorls  must have one ridge that makes a complete circuit  spiral, oval, or circular B. Central Pocket Loop  same as above

18. C. Double Loop  2 loops in one print D. Accidental  contains 2 or more patterns  or a pattern not covered

19. 3. Arches Ridge patterns that enter on one side of the finger and exit on the other A. Plain Arch  ridges rise in the center in a wave-like pattern B. Tented Arch  sharp rise

21. Primary Classification Based on Sir Henry’s original system Look for the presence or absence of a WHORL Each whorl gets a number value and then a ratio is set up

22. The Ratio R. Index + R. Ring + L. Thumb + L. Middle + L. Little R. Thumb R.Middle R. Little L. Index L. Ring

23. Number Values 1 st Pair = 16 2 nd Pair = 8 3 rd Pair = 4 4 th Pair = 2 5 th Pair = 1 Arch/Loop = 0 *Now add 1 to both numerator & denominator = primary classification*

24. Detecting Fingerprints A. Latent Prints  invisible  left by sweat & oils B. Visible Prints  left when fingers touch a colored substance  blood, ink, paint

25. C. Plastic Prints  impressions left on soft material  putty, wax, soap, dust

26. Developing Latent Fingerprints

27. A. On Non-absorbent and Hard Surfaces Glass, mirrors, tile, plastic, etc. 1. Powders  adhere to sweat & oil 2. Super Glue Fuming  fumes stick to print & turn it white

31. 3. Reflected Ultraviolet Imaging System  RUVIS  Locates prints without powders or chemicals

34. B. On Porous and Soft Substances Paper, cardboard, cloth, etc. 1. Iodine Fuming  sublimation of iodine (solid  gas)  produces fumes that react with print  short lived

36. 2. Ninhydrin  reacts with amino acids in sweat  turns purple/blue  develops prints up to 15 years old

39. 3. Physical Developer  last resort b/c it washes away proteins  silver nitrate based  develops prints on articles that were wet at one time

41. Preservation of Prints Photograph the print Transport small objects with prints to crime lab  protect with cellophane Lift print with tape if on large or immovable objects

42. Digital Imaging Using computer software to enhance a print Adjusts color, brightness, & size Compares 2 prints side-by-side & looks for common features