Forensic Vocab

Locard’s Exchange Principle

The foundational theory that every contact between two objects leaves a trace; a perpetrator will take something from the scene and leave something behind

Chain of Custody

A chronological document or paper trail that records every person who has handled a piece of physical evidence to ensure it’s integrity

First Responders

The initial public safety officials or law enforcement officers to arrive at a crime scene

Primary duties are to secure the area and ensure safety

Physical Evidence

Any tangible object [ex. hair, DNA, fibers, weapons] that establishes a crime occurred or links a victim to a suspect

Trace Evidence

Small, often microscopic material left at a scene, like hair, soil, glass fragments, or clothing fibers

Latent Print

An invisible fingerprint, palm print, or footprint that is not visible to the naked eye and requires powders or alternative light sources to be revealed/seen

Impression Evidence

Objects or materials [tire tracks, footware soles, tool marks] that retain the physical characteristics of other objects pressed against them

Autopsy

A post-mortem medical examination and surgical dissection of a corpse in order to determine the precise cause and manner of death

CODIS

Also known as Combined DNA Index System

FBI managed database used by law enforcement to share and compare DNA profiles

Expert Witness

A qualified specialist (forensic scientist or toxicologist) permitted to present their scientific opinions to a court

Standard / Reference Sample

Physical evidence of a known origin used to compare against evidence gathered at the crime scene

Daubert Standard

The modern legal precedent and classical scientific method used by judges to evaluate if an expert’s testimony and methodology are scientifically valid

Frye Standard

A historical “general acceptance” test used in court to determine the admissibility of scientific evidence; it dictates that methods must be widely accepted in the specific scientific field