1. Statistical Significance of Evidence in Wayne William case:
Forensic experts found 28 different pieces of microscopic evidence (dog hairs, various fibers)

2. Yellow-green carpet fiber:
This fiber found on several victims had been made and sold to various carpet manufacturers from 1970 to During this period approximately 16,397 square meters of carpet were sold in the southern U.S.

3. The fibers were manufactured by the Wellman Corp
sold during
sold undyed to other companies.
West Point Pepperell Corp, of Georgia, made Luxaire carpet in English Olive green- only between

4. Calculate the following:
It was estimated that 82 average sized rooms in the state of Georgia had this carpeting. Since there were 638,995 houses in the Atlanta area, what is the probability of a house having this type of carpet?
1 out of __________ or ________%

5. Only about 16,000 yd2 were sold The odds were 1 in 7,792 now.
(out of 16 billion yd2 total) only 82 homes in Georgia should have that same carpet, ten years later.
The odds were 1 in 7,792 now.
BUT, Jimmy Ray Payne (killed a month earlier) had fibers that also matched carpets in the Williams’ car! This was a 1 in 3828 odds.
SO- the odds of both fibers found on victims matching Wayne Williams’ carpeting was 1 in 30 million!

6. What this proved:
The carpet in the William’s home was quite uncommon, thus finding one of these fibers on a victim made it highly probable that the victim had been in contact with Williams.
In this case, the presentation of statistical data was as important as the data itself.

7. Verdict
The jury found Wayne Williams guilty of two counts of murder in the first degree (Police suspected that Williams killed up to 28 males, but the prosecution focused on the last two found in the Chattahoochee river).
Wayne Williams is currently serving two life sentences

9. Fiber Evidence
A fiber the smallest unit of a textile material that has a length many times greater than its diameter.
can be spun with other fibers to form a yarn that can be woven or knitted to form a fabric.
Transfer of fibers and the significance of fiber associations are affected by:
The type and length of fiber used
the type of spinning method
the type of fabric construction

10. Matching unique fibers on the clothing of a victim to fibers on a suspect’s clothing can be very helpful to an investigation
whereas the matching of common fibers such as white cotton or blue denim fibers would be less helpful.
The discovery of cross transfers and multiple fiber transfers between the suspect's clothing and the victim's clothing dramatically increases the likelihood that these two individuals had physical contact.

11. the smallest unit of a textile material that has a length many times greater than its diameter.
can occur naturally as plant and animal fibers, but they can also be man-made.
can be spun with other fibers to form a yarn that can be woven or knitted to form a fabric.
Transfer and significance of fibers
type and length
spinning method
construction

12. Fiber Evidence
Fibers are gathered at a crime scene with tweezers, tape, or a vacuum. 
They generally come from clothing, drapery, wigs, carpeting, furniture, and blankets. 
For analysis, they are first determined to be
natural
manufactured
mix of both

13. Natural Fibers
Many different natural fibers that come from plants and animals are used in the production of fabric.
Cotton fibers are the plant fibers most commonly used in textile materials
The animal fiber most frequently used in the production of textile materials is wool, and the most common wool fibers originate from sheep.

14. Synthetic Fibers
More than half of all fibers used in the production of textile materials are synthetic or man-made.
Nylon, rayon, and polyester are all examples of synthetic fibers.
Fibers under a microscope
Cross-section of a man-made fiber
Images:

15. Types of Fibers Synthetic Natural Rayon Nylon Acetate Acrylic Spandex
Polyester
Natural
Silk
Cotton
Wool
Mohair
Cashmere

16. Fiber Comparison Can you tell the difference(s) between the cotton on
the left and the rayon on the right?

17. Protein Fibers
Wool—animal fiber coming most often from sheep, but may be goat (mohair), rabbit (angora), camel, alpaca, llama, vicuna
Silk—insect fiber that is spun by a silk worm to make its cocoon; fiber reflects light and has insulating properties

18. Mineral Fibers
Asbestos—a natural fiber that has been used in fire-resistant substances
Rock wool—a manufactured mineral fiber
Fiberglass—a manufactured inorganic fiber

19. Synthetic Fibers (Made from derivatives of petroleum, coal and natural gas)
Nylon—most durable of man-made fibers; extremely light weight
Polyester—most widely used man-made fiber
Acrylic—provides warmth from a lightweight, soft and resilient fiber
Spandex—extreme elastic properties

20. Polymers
Synthetic fibers are made of polymers which are long chains of repeating chemical units.
The word polymer means many (poly), units (mer).
The repeating units of a polymer are called monomers.

21. Steps of Fiber Analysis
Bag clothing items individually in paper bags. Make sure that different items are not placed on the same surface before being bagged.
Make tape lifts of exposed skin areas of bodies and any inanimate objects
Removed fibers should be folded into a small sheet of paper and stored in a paper bag.

22. The first step in fiber analysis is to compare color and diameter. 
Microscopic observation
Burning—observation of how a fiber burns, the odor, color of flame, smoke and the appearance of the residue
Thermal decomposition—gently heating to break down the fiber to the basic monomers
Chemical tests—solubility and decomposition

23. Microscopy Fibers should be first examined with a stereomicroscope.
Physical features such as:
crimp, length, color, relative diameter, luster, apparent cross section, damage, and adhering debris should be noted.
Fibers are then tentatively classified into broad groups
synthetic, natural, or inorganic.
If the sample contains yarns, threads, or sections of fabric, construction should be recorded

24. The Scanning Electron Microscope
(SEM) bombards a specimen with a beam of electrons instead of light
Produces a highly magnified image from 100x to 100,0000
Depth of focus 300X better than optical systems at similar magnification

25. Bombardment of the specimen’s surface with electrons
Produces x-ray emissions
Characterize elements present in the material under investigation

26. Dental Plaque

27. Bread Mold Aspergillus sp.)

28. Penecillium sp.

29. SEM: Hair and Hair follocles

30. SEM: hafnium nitride interface coating on carbon fibers

31. Dust Mite Family Reunion

32. PBS video about FBI needing to revise http://video. pbs
PBS video about FBI needing to revise CSI school: NCSSM analysis video