All About Evidence Flashcards
Opinion Evidence
A forensic scientist offers their opinion as part of the body of evidence being considered in the case
Locard’s Exchange Principle
Every contact results in leaving behind a trace of something, or evidence
Transfer Evidence
Exchange of material that is the evidence of an interaction
Inclusive Evidence
Evidence that is included in the population of items that came from the crime scene
[Example: Dirt and grass on a pair of shoes supports the idea that a crime took place at a baseball field, and adds individual to a list of people that could have been at the field]
Exclusive Evidence
Evidence that is excluded from the population of items that came from the crime scene
[Example: If neither person lived in the city where the baseball field was located] I don’t fucking know this doesn’t make any sense to me
Indeterminate Evidence
Evidence that doesn’t help answer the question related to location
[Example: Beach sand on shoes found at the baseball field]
Testimonial Evidence
Another term for eyewitness evidence
Physical Evidence
Raw material; needed by forensic scientists for processing
Admissibility
Quality of being acceptable or valid as evidence
Who decides if scientific evidence is admissible?
The court
Admissible Evidence
Is reliable and relevant to the case at hand; the methods used are scientifically accurate and reliable
Frye Standard
A procedure, technique, or principle must be generally accepted by the scientific community
Daubert Standard
Scientific techniques should be tested, subject to review by other scientists, and the error rate should be known
(Aka the judge is responsible for determining if the evidence is relevant)
Gatekeeper
Term used to refer to the judge who is in charge of determine admissibility
Admissibility under the trilogy model is judged on…
Reliability and utility
Inculpatory Evidence
Shows guilt of a suspect
Aka incriminating evidence
Exculpatory Evidence
Shows innocence of a suspect
Circumstantial Evidence
Could have arisen for non-criminal reasons
ie a defendant’s blood is found at a crime scene and linked to her by DNA results; the DNA alone does not speak innocence or guilt, but more information can be inferred from this
Deductive Reasoning
Equivalent of mathematical reasoning;
the core concepts must be true, ie a bloodstain test comes back with the amelogenin type of X, X. Only females have an amelogenin type of X, X, so the bloodstain pattern must have come from a female
Inductive Reasoning
Uses existing data to make predictions and generalizations
For example, most serial killers are men, so an investigation into a series of murders might start based on the theory that the killer is male
Abductive Reasoning
Based on gathering what is known and using this information to come up with the simplest and most likely explanation
Direct Evidence
Shows a fact to be true unless disproven
Indirect Evidence
Evidence is transferred from the source to the location between one or more intermediate objects
Standard Exemplar
Pure material of a commercial origin
Control/Blank Exemplar
Material without apparent transfer, used to document background noise and contamination
Elimination Exemplar
Material known to be from non-culprits, used to quickly eliminate non/evidence
Individualization
Process of giving a piece of evidence or its source a specific unique identity based on individual characteristics
The basic hypothesis tested during evidence identification
That an exemplar and an unknown are the same (easily falsifiable)
Contrite Fallibilism
Awareness that we can never prove something 100% and there may be alternative explanations
Evidence Analysis Process
Detection Preservation Comparison/Identification Association Reconstruction
Comparative Analyses
Determines whether two things are the same across different features, such as appearance or physical/chemical characteristics
Reference/Known Exemplar
Intact materials collected from suspects or scene
Type I v Type II error
Type 1 errors are more severe, and can cause false incrimination
Type 2 errors can cause false exoneration, and are less severe than Type 1 errors
Probative Value
Probability of evidence to reach its proof purpose of a relevant fact in an issue
Class Characteristic
Trait(s) shared by all members of a class of objects
ie all round objects are circular
Conflicting Evidence
Contradicts other evidence or theories
Corroborating Evidence
Evidence that confirms other evidence or theories
Direct vs Circumstantial
Direct has a low probability of fallibility, while circumstantial has a high probability
Real Evidence
- Collected at Scene
- Processed and presented as authentic
- Allows jury to draw their own conclusions
Demonstrative Evidence
- Scene documentation
- Created after analysis
- Explains the scene of explains an analysis
Kumho Tire
Daubert factors apply to all experts
Joiner
Scientific evidence must be specifically relevant
Conclusive Evidence
Evidence so overwhelming that it proves either guilt or innocence
Derivative Evidence
Discovered through illegal means, and as such, cannot be used in trial
Foundational Evidence
Determines the admissibility of other evidence
Proxy Data
Data seen as remnants of an event
Controls
Materials with a known source; used for comparison with unknown evidence
Coincidental Associations
Two things which have never been in contact with each other, however have items on them that are analytically indistinguishable at class level
