Chapter 2: Types of Evidence

Testimonial evidence

a statement under oath: also known as direct or prima facie

Physical evidence

any object or material that is relevant in a crime: known as real.

Hair, fiber, fingerprints, documents, blood, soil, drugs, toolmarks, impressions, glass

Paul Kenneth Keller

Serial arsonist. Used forensic hypnosis on witness to create a sketch.

Coral Eugene Watts

Served sentence for burglary and intent to murder. Eyewitness said he saw him kill a girl 25 years earlier, and was found guilty.

Ronald Cotton

Convicted of robbery and rape, victim ID’d Cotton in a lineup, but DNA testing later proved Cotton innocent.

Innocence Project

Organization dedicated to exonerating wrongfully convicted people through DNA evidence.

Transient evidence

Evidence is temporary; easily changed or lost: usually observed by the first officer at the scene.

Odor, temperature, imprints/indentations

Pattern evidence

Produced by direct contact between a person and an object or between 2 objects; leaves a pattern, imprint, marking

Body position, tool marks, clothing distribution, gunpowder residue

Conditional evidence

Produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances or sequence within a particular event

Transfer evidence

produced by a contact between person(s) and object (s), or between person(s) and person (s); leaves trace

Hair, fibers, paint, backspatter, GSR, soil, etc.

Associative evidence

Something that may connect the victim or suspect with a scene or with each other.

Drivers license, clothing, fingerprints, footprints, hair

Control sample

used to validate the testing procedure

Indirect evidence

does not prove a fact, only basis for inference

ex. Someone says they saw someone driving erratically, later the person is found and takes a breathalyzer with results over .08, inferred that they were drunk driving.

Circumstantial evidence

Based on suggestion rather than personal knowledge or observation.

ex. Same size shoe print, same hair color as suspect found at scene

Biological evidence

Blood, semen, saliva, sweat, tears, hair, bone, tissues, urine, animal material, insects, bacteria, fungi, botanical material

Chemical evidence

Fibers, glass, soil, gunpowder, metals, minerals, narcotics, drugs, paper, ink, cosmetics, paint, lubricants, fertilizer

Miscellaneous evidence

voice analysis, polygraph, photography, vehicle identification

Individual evidence

can be identified with a particular person or a single source (fingerprints, DNA, something with tear marks, etc.)

Class evidence

Common to a group of objects or people (hair color, blood type, etc.)

Recognition

the ability to distinguish important evidence from unrelated material

Preservation

through the collection of proper packaging of evidence

Identification

using scientific testing

Comparison

of class characteristics measured against those of known standards or controls

Individualization

in demonstrating that the sample is unique, even among members of the same class

Interpretation

giving meaning to all the information

Reconstruction

of events in the case

Richard Crafts

Convicted of murdering his wife; one of the first cases with no body and showed physical evidence was extremely important