Fingerprints

1. “Every human being carries with him from his cradle to his grave, certain physical marks which do not change their character, and by which he can always be identified – and that without shade of doubt or question. These marks are his signature, his physiological autograph, so to speak, and this autograph cannot be counterfeited, nor can he disquise it or hide it away, nor can it become illegible by the wear and mutations of time.” Pudd’nhead Wilson, Mark Twain

2. Fingerprints Chapter 4

3. Fingerprint • Mixture of water, oils, salt, and dirt

4. History • Alphonse Bertillon (1902) – credited for solving the first murder using fingerprints, also first to document incoming prisoners with a photograph • Galton and Henry (1888) – developed system for classifying fingerprints still used in US today • Ivan Vucetich (1891) – began taking first ten cards

5. Classification 3 Basic Patterns Loop Whorl Arch

6. Loop One or more ridges entering from one side, curving and going out same side Loop even if only one ridge exits the side it enters 2 subgroups Radial: opens to thumb (radius) Ulnar: opens to pinky (ulna) **more common 65%

8. Whorl Must have atleast 2 deltas and a core 4 subgroups Whorl Central pocket Double Accidental 20%

10. Arch Least common, simplest Ridges enter one side and exit the other No delta or core 2 subgroups: Plain arch Tented arch Sometimes confused with loops No delta or core

11. Plain Arch

12. Tented Arch

14. How Do We Find a Match? • Method developed by Edward Henry to classify all sets of ten fingerprints • 1,024 groups • Manual comparisons still very common

15. Steps in Classification • Primary Classification • Identify any whorls • Rt Index Rt ring Lt thumb Lt middle Lt little 16 8 4 2 1 +1 ___________________________________________________ Rt thumb Rt middle Rt little Lt index Lt ring 16 8 4 2 1 +1

16. So…….. • Whorl on left thumb and right middle finger • Rt Index Rt ring Lt thumb Lt middle Lt little 16 8 4 2 1 +1 ___________________________________________________ Rt thumb Rt middle Rt little Lt index Lt ring 16 8 4 2 1 +1 0+0+4+0+0+1 = 5 ------------------------- 0+8+0+0+0+1 = 9

17. Pattern Frequency

18. Ridge Classification • Minutiae – tiny ridge characteristics

19. Fingerprints as Evidence • 8-12 points of minutiae usually provide enough for conviction • No amount legally required • Print will have 150-200 minutiae, but prints must be rolled properly

20. So, do you think you can alter your fingerprints?

21. Now, label the minutiae in Figure 8

22. Types of Prints • Plastic prints – (indented or molded) 3-D • Paint, putty, soap, wax, gum, candy bar • Visible prints – print on colored material • Latent prints – invisible and must be developed (deposits of perspiration and oil)

23. u

24. Developing Prints • Dusting • Hard, nonabsorbent surfaces • Chemical methods • Soft, porous surfaces (paper, styrofoam) • Iodine – reacts with fatty oils on finger • Ninhydrin – reacts with amino acids and turns orange or purple • Silver nitrate – reacts with salt and turns into silver chloride which then turns into dark silver oxide (photographs) • Superglue – cyanoacrylate ester adheres to create permanent print • Alternate Light Sources

25. Order of Tests • When only one piece of evidence, use the tests that cause the least damage to the print.

26. History of Fingerprints • Timeline

27. Anatomy of Fingerprints • Even twins have different fingerprints • Papillae under the epidermis cause the friction ridges to occur

28. Other Methods of Visualizing Fingerprints • Digital enhancement • IAFIS (Integrated Automated Fingerprint Indentification Systems) • Fluorescent dyes • Lasers • IAFIS (Integrated Automated Fingerprint Identification System) • More than 46 million records • Live scan devices