Chap 1 The Forensic Sciences Flashcards
What is forensics?
The use of science in legal matters
Define “evidence”.
The stuff we use to prove things.
What is modus operandi (MO)?
These are features a perpetrator deems necessary to commit a crime. Ie. Wearing gloves to break into a house
What is a signature?
It fulfills a psychological or an emotional need for the perpetrator. Ie. Breaking into a house for money/goods but leaving a message on the wall in lipstick before they go.
L _ _ _ _ d’s Theory of Exchange suggests whenever there is contact between two sources, there is an exchange of evidence.
Locard’s Theory of Exchange.
What does corpus deliciti establish?
A person can’t be tried for a crime unless there is proof a crime occurred.
How is shoe size an example of a class characteristic?
Shoe size is an attribute common to a group.
What is the difference between an MO and a class characteristic?
An MO is NECESSARY to commit the crime. A signature is an additional tack on to fulfill a psychological/emotional need.
Why are fingerprints considered an individual characteristic?
They are an attribute that is individual specific. It can be traced back to a particular individual.
What is the difference between direct evidence and circumstantial evidence?
Direct evidence is reporting something experienced firsthand (I saw, heard, smelled, etc). Circumstantial evidence is an assumption or an inference is made.
Ex from class:
Direct Evidence: I saw Jack shoot Jill.
Circumstantial Evidence: Jack was holding a smoking gun and Jill was on the ground. Jack must have shot Jill.
Relevant evidence sways people towards innocence or guilt. In what cases can relevant evidence be excluded from court?
1) The testimony violates C _ _ _ _ _ _ _ _ _ _ _ _ _ y or privilege.
2) It may be P _ _ _ _ _ _ _ e. For example, pictures of decapitated children may inflame the jury and seal a verdict on sight.
1) Confidentiality
2) Prejudice
Graphic crime scene evidence undergoes the balancing test. Why is this test necessary?
To prevent evidence that will prejudice/inflame the jury. This is done to ensure the defendant gets a fair trial.
What’s the difference between a lay witness and an expert witness? Hint: What are they allowed to testify about?
A lay witness is an average Joe. They can testify on things they encounter frequently in their daily life. Ie. I was going the speed limit when that person passed me on the highway. They were speeding before the accident. An expert witness has special knowledge, training, or education in their field. Ie. After analyzing the evidence, I believe the man was going 80mph in a 50mph zone prior to the accident.
