Criminal Investigation Fundamentals Flashcards

DNA evidence at a scene is most reliably collected from a touched surface using:

Answer: A sterile swab moistened with distilled water

Touch DNA is recovered by swabbing surfaces with a sterile, lightly moistened swab to lift shed cells.

What is the primary purpose of AFIS in a criminal investigation?

Answer: Searching and matching fingerprints against a database

The Automated Fingerprint Identification System compares latent or known prints against large fingerprint databases.

Latent fingerprints on a non-porous surface like glass are commonly developed using:

Answer: Fingerprint powder or cyanoacrylate (superglue) fuming

Powder and superglue fuming are standard methods for visualizing latent prints on smooth, non-porous surfaces.

Luminol is used at a crime scene primarily to detect:

Answer: Trace amounts of blood that may have been cleaned up

Luminol chemiluminesces in the presence of the iron in hemoglobin, revealing latent or cleaned bloodstains.

Why must biological evidence such as bloodstained clothing be packaged in paper rather than sealed plastic?

Answer: Plastic traps moisture and promotes mold and DNA degradation

Plastic retains moisture that fosters bacterial growth and degrades biological samples, so breathable paper is used.

The Daubert standard governs what aspect of forensic evidence?

Answer: The admissibility of expert and scientific testimony in court

The Daubert standard guides judges in assessing whether scientific expert testimony is reliable and admissible.

When collecting a firearm as evidence, investigators should avoid:

Answer: Inserting anything into the barrel or wiping the surfaces

Inserting objects into the barrel or wiping the weapon can destroy residue, prints, and trace evidence.