Forensics Unit 2: Crime Scene Investigation and Evidence

Vocabulary study flashcards covering key terms, protocols, search methods, evidence packaging rules, and case study errors from Forensics Unit 2.

Primary crime scene

The location where the crime actually occurred.

Secondary crime scene

A location connected to a crime where the crime itself did not occur.

Chain of custody

A record of everyone who handled or possessed evidence after collection.

Biological evidence

Evidence from living organisms, such as blood, saliva, hair, or tissue.

Crime scene perimeter

A secured boundary established around a crime scene to keep unauthorized people out.

Cross contamination

The accidental transfer of evidence between objects, people, or locations.

Linear search

A search where investigators search in straight, parallel lines across a crime scene.

Spiral search

A search pattern where an investigator searches in a spiral pattern, moving inward or outward.

Final crime scene sketch

A neat, accurate drawing of the crime scene made to scale.

Rough crime scene sketch

A preliminary drawing with measurements written on it, not necessarily to scale.

Staged crime scene

A crime scene deliberately altered to mislead investigators, sometimes to make one crime appear to be another.

Crime scene reconstruction

Using evidence and background knowledge to develop a hypothesis about how a crime occurred.

Separating eyewitnesses

A procedural step performed to prevent witnesses from influencing each other's memories and statements.

Difference between primary and secondary crime scenes

Primary is where the crime occurred; secondary is another location connected to the crime.

Primary and secondary crime scenes (example)

A robbery happens in a house (primary), and stolen property is found in a car (secondary).

Seven S's of crime scene investigation

Secure the scene, Separate witnesses, Scan the scene, See the scene, Sketch the scene, Search for evidence, Secure and collect evidence.

Secure the scene

Establish a perimeter and prevent unauthorized entry.

Separate witnesses

Keep witnesses apart to prevent them from influencing one another.

Scan the scene

Survey the area and identify important locations and potential evidence.

See the scene

Photograph the entire scene and individual pieces of evidence.

Sketch the scene

Draw the layout and record measurements and evidence locations.

Search for evidence

Use a systematic search pattern to locate evidence.

Secure and collect evidence

Package, label, and preserve evidence properly.

Five crime scene search patterns

Linear, Grid, Spiral, Zone, and Wheel.

Linear (strip) search

A pattern where searchers walk in straight, parallel lines.

Grid search

A pattern where searchers conduct two perpendicular sets of parallel-line searches.

Spiral search pattern

A pattern where a searcher follows a spiral path inward or outward.

Zone (quadrant) search

A pattern where searchers divide the scene into smaller sections and search each separately.

Wheel (ray) search

A pattern where investigators move along straight paths radiating from a central point.

Best search patterns for a single investigator

Spiral and linear, because one person can follow a clear search path.

Best search patterns for a team

Grid, linear, and zone, because the work can be divided among investigators.

Packaging biological evidence

Dry it first, then package in paper bags or envelopes to prevent mold.

Packaging trace materials

Use paper bindles (druggist folds), then place inside sealed envelopes.

Packaging liquid evidence

Use properly sealed, leakproof containers.

Packaging arson remains

Use airtight metal cans or approved glass containers to preserve volatile residues.

Packaging powder evidence

Use sealed containers or paper bindles inside envelopes to prevent loss.

Drying biological evidence

The practice performed to prevent moisture buildup, mold, and decomposition.

Separate packaging of evidence items

The procedure of packaging items individually to prevent cross contamination.

JonBenet Ramsey mistake 1

Police did not adequately secure the house and allowed friends and family inside.

JonBenet Ramsey mistake 2

John Ramsey was allowed to search the house and moved JonBenet's body after discovering it.

JonBenet Ramsey mistake 3

Witnesses were not properly separated, allowing potential influence on statements.

JonBenet Ramsey investigation mistakes (impact)

They risked contamination and disturbance of evidence, making it harder to reconstruct events and identify the perpetrator.