Crime Scene Flashcards

What are the three types of fingerprints?

Patent, Plastic, and Latent.

What is a patent fingerprint?

A visible print due to substances like blood, ink, or dirt.

What is a plastic fingerprint?

An impression left in soft surfaces like wax, putty, or soap.

What is a latent fingerprint?

An invisible print requiring enhancement techniques.

What is the composition of fingerprints?

98% water, 2% grease, oil, salts, and amino acids.

What are the three main fingerprint patterns?

Loops, Whorls, and Arches.

What percentage of fingerprints are loops?

70%.

What percentage of fingerprints are whorls?

25%.

What percentage of fingerprints are arches?

5%.

What are the two types of loops?

Ulnar (opens toward pinky) and Radial (opens toward thumb).

What are the four types of whorls?

Plain, Central Pocket, Double Loop, and Accidental.

What are the two types of arches?

Plain and Tented.

What is ridge counting?

Counting the number of ridges between the core and the delta.

Name a technique for locating latent prints.

Oblique lighting.

When should powder be used for fingerprint development?

On hard, non-absorbent surfaces.

What are the three types of fingerprint powders?

Regular, Magnetic, and Fluorescent.

What color powder should be used on dark surfaces?

Grey, white, or silver.

What is the purpose of magnetic powder?

Effective on rough, porous surfaces.

What type of powder fluoresces under UV light?

Fluorescent powder.

What chemical reacts with amino acids in sweat?

Ninhydrin.

What color does ninhydrin turn fingerprints?

Purple (Ruhemann’s Purple).

What is a physical developer used for?

Developing prints on wet porous surfaces.

What chemical is used in superglue fuming?

Cyanoacrylate.

What does superglue fuming do?

Creates a white polymer on fingerprints.

What does amido black detect?

Blood proteins.

What color does amido black stain?

Blue-black.

What does leucocrystal violet react with?

Blood hemoglobin.

What database stores fingerprint records?

IAFIS.

What are the five steps of crime scene processing?

Secure, Survey, Document, Collect, Release.

What is physical evidence?

Any object linking a crime to a suspect or victim.

What does Locard’s Principle state?

Every contact leaves a trace.

What is chain of custody?

A documented trail of evidence handling.

What is the 4th Amendment?

Protection against unlawful searches and seizures.

What case established the exclusionary rule?

Weeks v. United States.

What is primary evidence?

Evidence that directly proves a fact.

What is secondary evidence?

Evidence derived from primary evidence.

What is the Brady Rule?

Prosecution must disclose exculpatory evidence.

What case changed how courts handle hearsay?

Crawford v. Washington.

What is exculpatory evidence?

Evidence that supports the innocence of a defendant.

What is impeachment evidence?

Evidence challenging a witness’s credibility.

What PPE should be worn at crime scenes?

Gloves, masks, goggles, coveralls.

Name a search pattern used at crime scenes.

Grid method.

What is the strip search method?

Searching in parallel lines.

What is the spiral search method used for?

Small or confined crime scenes.

What is used to detect gunshot residue?

Swab or disc lift techniques.

How soon should GSR be collected?

Within 4 hours.

What is a cartridge made of?

Bullet, gunpowder, primer, and casing.

What is rifling?

Spiral grooves in a gun barrel to improve accuracy.

What is an exemplar?

A known sample for handwriting comparison.

What is an altered document?

A document with changed portions.

How should wet evidence be packaged?

Air-dried first, then placed in paper bags.

What should not be used for biological evidence?

Plastic packaging.

How should DNA samples be stored?

Refrigerate liquid samples; freeze tissue samples.

What are three methods of collecting trace evidence?

Picking, Taping, Vacuuming.

What is fracture matching?

Aligning fragments to confirm they were once joined.

What does toxicology test for?

Drugs, alcohol, poisons.

What are common toxicology specimens?

Blood, urine, hair, liver, gastric contents.

What is a clandestine lab?

An illegal drug manufacturing site.

What are indicators of a clandestine lab?

Strong odors, chemical containers, improvised equipment.

How should digital evidence be stored?

Anti-static packaging, avoid extreme temperatures.