reconstructive evidence allows investigators to gain an understanding of the actions that took place at the scene; a broken window, a blood spatter pattern, bullet paths and shoe prints.

evidence of unknown origin; these samples could be found at a crime scene, transferred to an offender during commission of a crime, or recovered from more than one crime scene.

Special lighting device that produces visible and invisible light at various wavelengths to help investigators locate and visually enhance items of evidence (e.g., fluids, fingerprints, clothing fiber [..]

any evidence that can link a person or an item to the scene of the crime.

physical evidence such as bodily fluids that originated from a human, plant or animal.

The process used to maintain and document the chronological history of the evidence. Documents record the individual who collects the evidence and each person or agency that subsequently takes custody [..]

The unwanted transfer of material from another source to a piece of physical evidence. The inadvertent touching of a weapon, thereby adding fingerprints to it is an example of evidence contamination.

material of a known source that presumably was uncontaminated during the commission of the crime.

The unwanted transfer of material between two or more sources of physical evidence. For example, improperly collecting biological evidence such as blood could lead to one sample mixing with another sa [..]

material of a known source taken from a person who had lawful access to the scene.