Locard's Exchange
This French criminologist developed the principle that "every contact leaves a trace."
Who is Edmond Locard?
This 1923 court case established the first major standard for admitting scientific evidence in court.
What is Frye v. United States?
This is the first step investigators take when arriving at a crime scene.
What is secure the scene?
This type of evidence can be counted, measured, or weighed and includes items like weapons or documents
What is physical evidence?
These three methods are essential for documenting a crime scene before any evidence is moved.
What are photography, sketching, and note-taking?
According to Locard's principle, when two objects come into contact, this always happens between them.
What is the transfer of material?
The Frye standard requires that scientific evidence be accepted by this group before being admitted in court.
What is the relevant scientific community?
The investigator is looking over the scene
What is Scanning the scene?
Evidence is classified as either this type, which proves a fact directly, or circumstantial, which requires inference.
What is direct evidence?
Crime scene photographs should include these three types of shots to properly document the scene.
What are overall/wide shots, mid-range shots, and close-up shots?
These are two examples of trace evidence that might be transferred according to Locard's principle.
What are fibers, hair, paint chips, glass fragments, soil, or pollen? (Accept any two)
This 1993 Supreme Court case replaced the Frye standard with new criteria for scientific evidence
What is Daubert v. Merrell Dow Pharmaceuticals?
This type of search pattern involves investigators walking in straight, parallel lines across the crime scene.
What is a grid or line search?
This term describes evidence that could have come from multiple sources and cannot be linked to a specific person or object.
What is class evidence?
A crime scene sketch must include these two essential measurement components.
What are scale/measurements and a north arrow/compass direction?
This is why investigators must wear protective clothing and change gloves frequently at crime scenes
What is to prevent contamination and unwanted transfer of evidence?
These are three of the four Daubert criteria judges use to evaluate scientific evidence.
What are testability, peer review/publication, error rates, and general acceptance?
Evidence should be collected from this area first, then moving outward in a circular pattern.
What is Spiral method?
This type of evidence can be linked to a specific source with high certainty, like DNA or fingerprints.
What is individual evidence?
This information must be recorded for every piece of evidence collected, including location, time, and collector's name.
What is evidence documentation or evidence log?/ chain of custody log?
Locard's principle applies in both directions, meaning the perpetrator leaves evidence behind AND takes this away from the scene.
What is evidence from the victim or crime scene?
Under Daubert, judges serve in this role when deciding whether scientific evidence is admissible.
What is gatekeeper?
This is the proper order for processing evidence: photograph, measure, collect, or collect, photograph, measure.
What is photograph, measure, then collect?
When analyzing evidence, investigators must maintain this unbroken record showing who handled the evidence and when.
What is chain of custody?
This is a crucial element of a crime scene sketch that indicates the position of evidence.
What is a legend or key?