Chapter 3: The Nature of Evidence Flashcards
What is a trier-of-fact?
The trier-of-fact is the jury or judge in a trial that determines guilt or innocence. They make this call by listening to the facts or statements of the case to make a determination.
What is evidence?
Evidence is information that is given in a legal investigation to make a fact or proposition more or less likely. It can be in the form of personal testimony, language of documents, or production of material objects. For example, someone is seen leaving the scene of a homicide with a gun, and it is later shown by scientific examination that bullets removed from the body were fired from that gun.
Name four kinds of evidence.
Demonstrative evidence: a preparation of evidence generated to understand the incident and testimony. For example, diagrams of hair characteristics, a computer simulation of a crime scene, or a demonstration of bloodstain pattern mechanics.
Circumstantial evidence: evidence based on inference and not on personal knowledge or observation.
Conclusive evidence: evidence that is so strong, it overbears any other evidence to the contrary.
Conflicting evidence: evidence that is irreconcilable that comes from different sources.
What is exculpatory evidence?
Evidence tending to establish a criminal defendant’s innocence.
What is proxy data?
Proxy data is the remnants of events left behind, it is not seen as it is created. It is the evidence analyzed by forensic scientists to determine the relationship between people, places, and objects.
How is direct transfer different from indirect transfer? Give an example.
Direct transfer involves evidence that is transferred from a source to a location with no intermediaries. An indirect transfer involves one or more intermediate objects. For example, direct transfer would be a person sitting in their chair at home and getting dog hair on their pants. Indirect transfer would occur if the person’s coworker sat in their chair, and dog hair transferred from the person’s pants to the chair to the coworker’s pants. The coworker did not come into contact with the dog, but the dog’s hair is now on their pants.
What is persistence in relation to evidence?
Persistence is the second part of transfer. Once the evidence transfers, it will remain (persist) in that location until it further transfers, degrades, or is collected as evidence.
What is contamination evidence?
Contamination evidence is a transfer that takes place after the crime has stopped, and is an undesired transfer of information between items of evidence.
What is class-level evidence?
Class is a group of objects with similar characteristics. Class-level evidence is evidence that falls within a class.
What does it mean to identify something?
Identification is the examination of the chemical and physical properties of an object and using them to categorize the object as a member of a group.
What is a common source?
The definition of common source depends on the material in question, the mode of production, and the specificity of the examinations used to classify the objects. The common source of a piece of evidence is where they both came from.
If you have individualized two pieces of evidence, how many common sources could they come from?
If an object can be classified into a group with only one member (itself), it is said to be individualized. An individualized object has been associated with one and one one source, because it is unique. Two pieces of evidence that are each individualized would then each come from one common source.
What is the difference between questioned and known evidence?
Questioned evidence is evidence that may lead to information pertaining to the crime, but we do not know the source and cannot yet prove its significance. Known evidence is evidence that has a known origin (has been analyzed), and is significant to the crime.
Context makes a piece of evidence known or questioned.
What is a control? How is it different from known evidence?
Controls are materials whose source is known and which are used for comparison with unknown evidence. It can help distinguish known evidence from questioned evidence. For example, if you have questioned evidence on a piece of clothing belonging to a victim, running a test on known blood would yield a positive test, and then running the test on the sample will identify if it is blood or not. This known blood is a positive control.
A negative control would be running a test that you would expect to have a negative result, and then running the test on evidence to determine if there is an unknown substance on the evidence.
What is the probative value of an item of evidence?
Probative value is the value it has in proving or disproving the hypothesis.
