CSI Midterm

Difference between individual and class characteristics?

Individual: Can be linked to one specific source (DNA, fingerprints, tool marks)

Class: Shared by a group/category (Shoe threat, tire type, blood type

What is cross contamination and how is it prevented?

Transfer of evidence between items or locations.

Prevented by wearing new gloves, using clean tools, separating evidence, and minimizing contact.

What are the basics of fingerprints and DNA in forensics?

Fingerprints:Unique ridge patterns (loops, whorls, arches); may be visible, plastic, or latent.

DNA: Found in blood, hair, saliva, skin; unique to individuals (except identical twins).

Ingredients of a good CSI

Detail-oriented, patient, observant, organized, team-oriented, knowledgeable about evidence handling, and focused on maintaining scene integrity.

What threatens crime scene integrity and how is it maintained?

Threats: loss, contamination, destruction

Maintained by: controlled entry, PPE, clear barriers, minimal disturbance, and full documentation.

What are the duties of the first responding officer?

1. Ensure safety

2. Provide emergency care (life>evidence)

3. Secure and control the scene

4. Establish perimeter

5. Document and debrief investigators.

How should a scene be controlled?

Remove unauthorized people, separate witnesses/suspects, maintain entry logs, and establish clear barriers

What are the main factors in assessing and setting a crime scene perimeter

1. Primary focal points

2. Natural entry/exit points

3. Secondary scenes

   1. Perimeter may expand as assessment continues

Forensic linkage triangle

It connects the victim, suspect, and crime scene through physical evidence, showing how each is linked to the others.

How is a crime scene perimeter set effectively

Start large, shrink as needed

Use barriers (tape, cones, vehicles)

Create buffer zones for safety and control (inner, working, outer areas)

Type of search patterns

1. Circle/spiral

2. Strip/Lane

3. Line

4. Grid

5. Zone

What hazards might investigators face?

Biological (blood/fluids), chemical structural, environmental, explosive and drug lab hazards

PPE in crime scene

Googles, face mask, tyvek suit, gloves, booties to protect from contamination and exposure

First responder vs csi duties

First responder: safety, medical aid, securing scene, documenting, debriefing.

CSI: Processes scene, documents, searches, collects evidence, maintains chain of custody.

Basic activities in CSI

1. Assessing

2. Observing

3. Documenting

4. Searching

5. Collecting

6. Analyzing

What’s the goal of the crime scene processing methodology

Follow a consistent, step-by-step process from least to most intrusive to preserve the full scene context

What does “going back in sequence mean in CSI?

When new evidence is discovered later, investigators must return to earlier steps (notes, photos, sketches) to document it fully before proceeding.

What five questions should a CSI ask the first responder?

1. What did you observe first?

2. What actions have been taken?

3. Who has entered the scene?

4. What’s the status of victims/witnesses/suspects?

5. How secure is the scene?

T or F: The use of a single layer of crime scene barrier tape could be considered ineffective at times

True