Crime Scene Investigation and Reconstruction: Types of Evidence, Standards, and Legal Requirements

Flashcards covering types of evidence, comparison standards and controls, and relevant constitutional amendments and legal concepts for search and seizure in crime scene investigation.

Direct evidence

Evidence that proves a fact without the necessity of an inference or a presumption that, when true, conclusively establishes that fact.

Circumstantial evidence

A series of facts that, although not the fact at issue, tends, through inference, to prove a fact at issue, usually a chain of circumstances from which a fair assumption can be made as to the validity of the fact at issue.

Testimonial evidence

Evidence given by lay or expert witnesses, for which the principal test is the credibility of the witness.

Physical evidence

Physical objects that are linked to the commission of a crime or tort.

Questioned item

An item with an unknown source, also referred to as 'unknown,' 'evidence,' 'crime sample,' or 'latent,' to be compared with an item from a known source.

Knowns

Items from a known source, which consist of standards (comparison and reference) and exemplars, used for comparison with questioned items.

Standards (in evidence)

Materials from a known source, comprising comparison standards and reference standards, used in laboratory analyses.

Comparison standards

Materials collected from a known source for comparison with a questioned sample to determine whether the questioned sample came from the same source.

Reference standards

Specimens kept in a reference collection by various laboratories, collected from different sources and authenticated, used to verify the type and composition of known samples in casework.

Exemplar

A sample of a comparison standard (known) that is collected or prepared for comparison with a questioned item, or the entire comparison standard used for the comparison.

Controls (in evidence testing)

Items tested simultaneously with the questioned item to reveal any problems associated with the integrity of the evidence item or the testing procedure, including background controls.

Fourth Amendment

Protects against unreasonable searches and seizures, requiring warrants to be issued upon probable cause and particularly describing the place to be searched and the persons or things to be seized.

Fourteenth Amendment

Ensures due process of law and equal protection of the laws to all citizens, and prevents states from abridging privileges or immunities of citizens or depriving them of life, liberty, or property without due process.

Search (legal definition)

Occurs when an expectation of privacy in an area that society is prepared to consider reasonable may be infringed by a warrantless intrusion.

Seizure of property

Occurs when there is some meaningful interference with an individual's possessory interest in that property by confiscating it by agents of the government.

Exigent circumstances

Court-recognized emergencies that justify warrantless intrusions into areas protected by the Fourth Amendment, such as to preserve life, prevent destruction of evidence, or stop a crime in progress.

Exclusionary Rule

A judicially created legal procedure requiring that evidence obtained during a search in violation of the Fourth Amendment must be excluded from a criminal trial as evidence against the defendant.