Lecture 1: Recap of Trace Evidence Flashcards
What was Locards Exchange Principle?
“It is impossible for a criminal to act, especially considering the intensity of a crime, without leaving traces of this presence.”
Every contact leaves a trace and there is a two way transfer.
What did Herbert Lon MacDonnell state?
“Physical evidence cannot be intimidated. It does not forget. It doesn’t get excited at the moment something is happening–like people do. It sits there and waits to be detected, preserved, evaluated, and explained.”
What does trace evidence do?
- It provides links between people and locations or objects and it is sometimes referred to as proxy data.
- Aids crime reconstruction
In the middle of the victim, scene and subject circles, what is the weight of evidence.
The center of the cirles is where the highest weight of evidence lies.
Why do we need trace evidence?
- Helps determine who did it
- Helps reconstruct a crime
- There is now a recommendation that no case should proceed on DNA evidence alone without specific sign-off by the Attorney General.
What is transference?
Where did the trace come from?
Every contact leaves a trace, just because you can’t see it doesn’t mean it isn’t there.
What is persistence?
- When was the trace transferred?
- What is the ability of the evidence to persist in a ranger of different conditions?
What is activity level?
How did the evidence get there?
