Physical Evidence

Common Types of Physical Evidence 1. Blood, Semen, and Saliva 2. Documents 3. Drugs 4. Explosives 5. Fibers 6. Fingerprints 7. Firearms and Ammunitions

Common Types of Physical Evidence 8. Glass 9. Hair 10. Impressions 11. Organs and Physiological Fluids 12. Paint 13. Petroleum Products 14. Plastic Bags

Common Types of Physical Evidence 15. Powder Residues 16. Serial Numbers 17. Soil and Minerals 18. Tool Marks 19. Vehicle Lights 20. Wood and other Vegetative Matter

The Examination of Physical Evidence Identification Comparison

Identification Determination of physical and chemical identity of a substance (to the exclusion of all other substances) with as near absolute certainty as existing analytical techniques will permit. - Drugs - Gasoline Residues - Explosive Residues - Blood, Semen, Hair

Comparison Analysis that subjects a suspect specimen and a control specimen to the same tests and examinations for the ultimate purpose of determining whether or not they have a common origin. 1. Individual Characteristics 2. Class Characteristics

Individual Characteristics Evidence that can be associated with a common source with an extremely high degree of probability. -Fingerprints 1 in 1x10 60 probability of two being the same -Tool Marks -Bullets

Class Characteristics Evidence that can be associated only with a group and never with a single source. -paint chips -blood type (Type A = 26%) -fibers -hairs

Crime-Scene Reconstruction It supports a likely sequence of events by the observation and evaluation of physical evidence, as well as statements made by witnesses and those involved with the incident.

Crime-Scene Reconstruction The following questions must be answered: -Was there more than one person involved? -How was the victim killed? -Were there actions taken to cover up what actually took place?

Crime-Scene Reconstruction Crime-Scene Reconstruction Law Enforcement Personal Medical Examiner Criminalist

The Wayne Williams Trial Atlanta’s Missing and Murdered Children Case (July 1979 – May 1981)

Case Background 30 missing and murdered black children and black young men during the 22-month period. Those found had died of asphyxiation. Investigators noticed unusual yellow-green nylon fibers and violet acetate fibers on many of the victims. The fiber findings were reported in February 1981, after which the victim were found unclothed or in undershorts.

The Yellow-Green Nylon Fibers Very coarse Lobed cross-sectional appearance Possibly from a carpet or rug Not readily recognized by industry experts

James Jackson Bridge May 22, 1981 – Atlanta P.D. and the FBI carry out a night time surveillance. Chicago Sun Times

James Jackson Bridge 2:00 am- They hear a loud splash and observe an automobile being driven slowly across the bridge. The driver was stopped and identified to be Wayne Bertram Williams. Two days later, Nathaniel Cater’s body was pulled from the Chattahoochee River.

Building a Case July 1981 – Wayne Williams was charged with the murders of Nathanial Cater and Jimmy Payne. Evidence included: Fibers, Hairs, and Bloodstains Presence on the James Jackson Bridge Known Relationships with the victims

The Williams’ Bedroom Carpet Made of yellow-green fiber matching that found on the victims. Fibers were manufactured by the Wellman Corporation 1967 – West Point Pepperell Corporation of Dalton, Georgia used the fibers to make “Luxaire” carpet from 12/1970 to 12/1971.

Probability Determinations West Point Pepperell reported purchases of Wellman 181B fiber during a 1-year period. The Wellman 181B fiber used to manufacture “Luxaire” carpet from 12/1970 until 12/1971, at which time a new fiber type replaced that Wellman fiber.

Probability Determinations In 1971, West Point Pepperell sold 5,710 square yards of English Olive “Luxaire” and “Dreamer” carpet in the Southern Region (10 states). In order to account for the carpet manufactured during 1971, but sold after that time, all the “Luxaire” dyed English Olive in color during 1972 to the Southern Region (10,687 square yards) added to the 1971 sales. Total = 16,397 square yards. (In 1979, existing residential carpeted floor space in the United States was estimated at 6.7 billion square yards.

Probability Determinations By assuming that this carpet was installed in one room, averaging 12 feet by 15 feet in size, per house, and also assuming that the total sales of carpet were divided equally among the 10 Southern States, then approximately 82 rooms with this carpet could be found in the State of Georgia.

Probability Determinations Information from the Atlanta Regional Commission showed that there were 638,995 occupied housing units in the Atlanta metropolitan area in November Using this figure, the chance of randomly selecting an occupied housing unit in the Atlanta metropolitan area and finding a house having carpet like the Williams’ carpet was determined to be 1 chance in 7,792 – a very low chance!

Other Fibers Linking Williams to the Victims

February 26, 1982 A Fulton County, Ga., Superior Court jury returned a verdict of “guilty as charged” on two counts of murder brought against Wayne Bertram Williams. The Atlanta Journal and Constitution