Forensics Unit 1 Notes
Chapter 2 – Types of Evidence
Evidence- Something that tends to establish or disprove a fact. Evidence can include documents, testimony,
and other objects
I.
Testimonial Evidence- what is said in court (under oath) by a competent witness; also called direct
evidence or prima facie evidence
a. Competent- Having the necessary ability, knowledge, or skill to do something successfully
b. Research has found that witnesses remember certain facts better than others
i. A witness that is physically similar to the offender is more likely to give an accurate
description
c. Victims of serious crimes remember facts for longer periods of time
d. Other physical factors or witnesses affect accuracy of observations
e. Interviewing techniques differ accuracy of eyewitness accounts
II.
Physical Evidence- tangible items that tend to prove some material fact; also called real evidence
a. Transient evidence - temporary; easily changed or lost; usually observed by the first officer at
the scene.
i. odor
b. Pattern evidence is produced by direct contact between a person and an object or between two
objects.
i. Blood spatter
c. Conditional evidence is 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.
i. Body – (temp…)
d. Transfer evidence is produced by contact between person(s) and object(s), or between person(s)
and person(s).
i. Paint / blood on a car
e. Associative evidence is something that may associate a victim or suspect with a scene or with
each other; e.g., personal belongings.
i. soil
f. Value of physical evidence
i. Back up testimony
ii. Link suspect
iii. Identify victim or suspect
iv. Reconstruction of crime