Please get out your notebook for notes

Evidence

Evidence Definition Evidence refers to information or objects that may be admitted into court for judges and juries to consider when hearing a case.

Three Types of Evidence Testimonial A testimony from a witness of a crime Physical any material items that are present at the crime scene or on the victims. Trace Refers to evidence that is found at a crime scene in small but measurable amounts.

Common Types of Physical Evidence Drug and toxic substance Resins, plastics Fingerprints Paints Explosive Residues Hair Gun Shot Residues (GSR) Serial Numbers Tissues Firearms and ammunition Documents Pollen Impressions Fibers Wood material Petroleum products Soil Feathers Alcohols (esp. Ethanol) Glass Bones Rubber Material Blood and Other Body Fluids Tool Marks

Evidence and Controls Determining the origin of an object or substance almost always involves a comparison with something similar or something that scientists know the origin of, such as a control. Evidence is always compared with a known or control

Types of Physical Evidence Trace Transient Conditional Indirect Circumstantial Evidence Individual Evidence Class Evidence

Trace Evidence Trace Evidence Examples: Physical evidence found in small but measureable amounts Examples: Hairs and fibers Skin cells

Locard’s Exchange Principle The value of trace (or contact) forensic evidence was first recognized by Edmund Locard in 1910. He was the director of the very first crime laboratory in existence, located in Lyon, France. The Locard’s Exchange Principle states that: "with contact between two items, there will be an exchange." For example, burglars will leave traces of their presence behind and will also take traces with them. They may leave hairs from their body or fibers from their clothing behind and they may take carpet fibers away with them.

The Atlanta Child Murders (1979 – 1981) Wayne Williams is thought to be one of the worst serial killers of adolescents in the U.S. history. His victims were killed and thrown into the Chattahoochee River in Georgia. Williams was questioned, because he was seen near where a body had washed ashore. Two kinds of fiber were found on the victims. The first kind was an unusual yellow-green nylon fiber used in floor carpeting. Through the efforts of the FBI and DuPont Chemical Company, the carpet manufacturer was identified. The carpet had been sold in only 10 states, one of them being Alabama, where Williams lived. Thus the fibers found on the victims were linked to the carpet fibers found in Williams’ home. Another victim’s body yielded the second type of fiber. This fiber was determined to be from carpeting found in pre-1973 Chevrolets. It was determined that only 680 vehicles registered in Alabama had a matching carpet. Williams owned a 1970 Chevrolet station wagon with matching carpet. The probability of both types of fibers being owned by the same person was calculated. The odds against another person owning both carpet types were about 29 million to one. Williams was convicted and sentenced to two life terms.

Atlanta Child Murders Reflection Read The Atlanta Child Murders (1979 – 1981) handout. On a half sheet of paper answer the following questions. When you are finished please turn your answers into the basket. Who is Wayne Williams and what did he do? What type of trace evidence was used to convict Wayne Williams? Who assisted the FBI in their investigation? What were the chances of someone owning both types of carpet types? Do you think this was enough evidence to convict Wayne Williams?

Trace Evidence and Bindles Due to the small nature of trace evidence, it is usually packaged twice. Once in a paper bindle Secondly in an envelope or baggie A bindle is a paper container.

How to make a bindle http://www.iape.org/resourcesPages/iapeDownload s/WestManheim/bindle.pdf

Transient Evidence Transient Evidence Examples: Temporary evidence that can be easily changed or lost and therefore must be recorded quickly. Examples: Odors Perfume,, cigarette smoke, gas Temperature Coffee pot, car hood, water in bath tub, dead body Imprints. Footprints in sand, fingerprints in dust, teeth marks in perishable food

Conditional Evidence Conditional Evidence Examples Produced by a specific action or event at the scene and must be observed and recorded Examples Lights Garage door Doors Windows Position of body Position of furniture

Indirect Evidence Indirect Evidence Evidence that does not prove or disprove a fact in question Evidence providing only a basis for inference about a disputed fact May prove something like the possession of controlled substances or driving under the influence.

Circumstantial Evidence Evidence based on suggestion rather than personal knowledge implies a fact without actually proving it The more circumstantial evidence there is the greater it weighs Probability and statistics are important Examples blonde hair found in hand of murder victim with black hair size 10 sneaker print near the body

Individual Evidence Individual Evidence Examples Evidence that can be related a single source Individualization always involves a comparison Narrows an identity to a single person or thing Examples DNA Fingerprints Handwriting

Class Evidence Class Evidence Examples Material that can be associated with a group ofitems that share properties or characteristics Narrows an identity to a group of persons or things Examples Blood Types Hair type DNA

Collecting Evidence

How to Collect Evidence Search the crime scene for possible evidence Number or Tag Evidence to be collected Record the Crime Scene Properly Record or Bag Evidence Properly Label all Evidence Fill out the Chain of Custody Send to Lab for Analysis

1. Searching For Evidence Five Crime Scene Search Patterns Grid Spiral In Spiral Out Parallel Zone

2. Numbering or Tagging Evidence Place markers next to the evidence you plan on collecting.

3. Record the Crime Scene Using pictures or a sketch artist Use rulers for scale Maintains the integrity of the original crime scene before evidence is moved for analysis.

4. Properly Record or Bag Evidence Determine the proper size of baggie or envelope. Do not put anything wet into a plastic bag. ALWAYS USE PAPER Wet things in plastic can grow moldy If taking a blood swab sample, always let the sample dry before packaging it. Seal Tightly

5. Properly Record or Bag Evidence Always Label Evidence with the Following Number Full Name Case Number Evidence Number Date of Collection Time of Collection John. Q. Doe Case #: 155647 Evidence#: 8 June 16, 1997 4:05 pm

6. Fill out the Chain of Custody The documented and unbroken transfer of evidence. Whenever you transfer evidence, you must sign a chain of custody log. This prevents evidence tampering by keeping track of the evidence at all times.

7. Send to Lab for Analysis Return to the lab and begin analyzing the evidence. As you do this, you must document and communicate to other areas of the law as they try to solve and close the case.