1. Trace Evidence Hair NS2232 - Littlefield

2. Trace Evidence--any small pieces of material, man-made or naturally occurring Most common examples: • Hair • Fiber NS2232 - Littlefield

3. Questions for Trace Evidence • What is it? • Is it man-made or natural? • What is its source? • How common is it? • Can it be identified to a single source? NS2232 - Littlefield

4. From hair one can determine: • Human or animal • Race • Origin • Manner in which hair was removed • Treated hair • Drugs ingested NS2232 - Littlefield

7. Hair Structure

8. Mosaic Pectinate Imbricate Petal Diamond petal Chevron Hair Cuticle Scale Types NS2232 - Littlefield

9. Scale Types Chevron Mosaic

10. Scale Types (cont) Diamond Petal Petal

11. Scale Types (cont) Pectinate Imbricate

12. Human Hair

13. Human Hair

14. Cat Hair

15. Cow Hair

16. Dog Hair

17. Bat Hair

18. Hair Structure

19. Hair Cortex The cortex gives the hair its shape. It has two major characteristics: • Melanin • Cortical fusi NS2232 - Littlefield

20. Hair Structure

21. Hair Medulla Types • Continuous • Intermittent or interrupted • Fragmented • Absent--not present NS2232 - Littlefield

22. Hair Medulla Patterns • Uniserial • Multiserial • Vacuolated • Lattice NS2232 - Littlefield

23. Human medulla • Human medulla may be continuous, fragmented or absent.

25. Rabbit medulla

26. Double Medulla

27. Medullary Index for human hair is generally less than 1/3. For animal hair, it is usually greater than 1/2. Medullary Index

28. Hair Growth • Anagen--hair that is growing • Catagen--hair at rest • Telogen--hair that is dying NS2232 - Littlefield

29. How/When Did It Leave? Anagen Telogen

30. Ethnicity Asian Black Caucasian

31. Cross-Sections Black Caucasian Asian

32. Dyed Human Hair

33. DNA • Mitochondrial • Nuclear NS2232 - Littlefield

34. Collection of Hair Evidence • Questioned hairs • Known/Control Sample • 50 full-length hairs from all areas of scalp • 24 full-length pubic hairs NS2232 - Littlefield

35. Hair Toxicology Advantages: • Easier to collect and store • Is externally available • Can provide information on the individual’s history of drug use. Collections must be taken from different locations on the body to get an accurate timeline. NS2232 - Littlefield

36. Buckling

37. Razor Cut

38. Egg Case