1. Fingerprints

3. Background Information Each fingerprint is made up of friction ridges, that do not change over time (unless scarring occurs) Fingerprints are formed in the womb Each fingerprint is a deposit of wastes when a person comes in contact with a surface 98 % is water & salts, 1% oils, 1% amino acids

4. Prints at a Crime Scene Divided into 3 types Patent Print Plastic Print Latent Print

5. Patent Print Can be seen with the naked eye Made by a hand that had blood, grease, oil, or any other sticky substance on it

6. Plastic Print Visible to the naked eye Formed when an impression is made in a soft substance such as putty, glue, dust, or butter

7. Latent Print Most common type Cannot be seen without applying powder or chemicals Substances adhere to the amino acids or oils in the fingerprint and make it visible

8. Patterns of Fingerprints 3 basic types of patterns Arch : 5% of population Loop: 65% of population Whorl : 30% of population

9. Basic Fingerprints ARCHLOOPWHORL Plain ArchLeft Radial Loop Plain Whorl Tented ArchLeft Ulnar LoopCentral Loop Whorl Right Radial Loop Double Loop Whorl Right Ulnar Loop Accidental Whorl

10. The Arch Formed when the ridge lines go from one side, rises in the middle, and leaves on the other side (like a wave) Tented arches are more pointed No ridgecount

11. Example of Arch

12. The Loop Ridge lines enters & exits on the same side of the finger Type is determined by the direction the ridges come & leaves If it is from the thumb-side of the finger, it is called a RADIAL LOOP If it is from the little finger side it is called an ULNAR LOOP

13. Examples of Loops

14. The Delta Whorls are subdivided using a ridge characteristic called a DELTA DELTA: Triangle pattern (ridge forks & nearby ridge) Whorls have 2 deltas, loops have 1 delta & arches have 0 deltas

15. The Whorl

16. Ridge Characteristics BIFURCATION (or fork): ridge splits into 2 friction ridges ENCLOSURE: forms an oval ENDING RIDGES: ridges that stop abruptly

17. Ridge Characteristics Continued SHORT RIDGES: begin & end abruptly, traveling a short distance RIDGE DOT: isolated ridge that’s length is approximately its width

18. Examples of Ridge Characteristics

19. Identifying Fingerprints 8-12 points of comparison must be in common to declare the 2 prints a match When a partial print is available, as many characteristics must be matched as possible Characteristics can be matched to the AFIS (Automated Fingerprint Identification System)

20. Example of Positive ID