Crime scene investigationAugust 19, 2014

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Objectives & Learner Profile

Describe the steps to take when processing a crime scene

Describe how to package evidence Explain the importance of preserving

chain of custody

Learner profile trait: Knowledgeable

Definitions

Crime scene – anywhere evidence may be located

Primary crime scene – the place where the crime was committed

(example: where someone was murdered)

Secondary crime scene – another place related to a crime

(example: where the body was dumped)

Steps for Crime Scene Investigation

First responders – the first people at a crime scene, usually police, firemen, or medical personnel.

Steps for Crime Scene Investigation

First responders – the first people at a crime scene, usually police, firemen, or medical personnel.

Duties of the first responders1. Scene management

Establish scene diameters Identify potential hazards Assist injured persons Search for and arrest suspect, if

possible

Steps for Crime Scene Investigation

First responders – the first people at a crime scene, usually police, firemen, or medical personnel.

Duties of the first responders1. Scene management

Establish scene diameters Identify potential hazards Assist injured persons Search for and arrest suspect, if

possible

Discuss with a partner:What is the importance of scene management?

What is the drawback of first assisting injured persons?

Steps for Crime Scene Investigation

Duties of the first responders

2. Secure the crime scene – prevent access by unauthorized personnel▪ Use physical barriers like vehicles and/or crime

scene tape▪ Establish a crime scene security officer▪ Keep a security log of all entries and exits▪ May use multilevel security

Steps for Crime Scene Investigation

Duties of the first responders

▪ May use multilevel security

Level 1: Restriction of general public; medial allowedLevel 2: Offical business only; command center hereLevel 3: Highest security

Steps for Crime Scene Investigation

Duties of the first responders

▪ May use multilevel security

Level 1: Restriction of general public; medial allowedLevel 2: Offical business only; command center hereLevel 3: Highest security

Discuss with a partner:

What important principle of forensics is related to the need to secure the crime scene?

What is the benefit of multi-level security?

Steps for Crime Scene Investigation

Duties of the crime scene investigator3. Develop a plan and coordinate

investigation• Review existing security and adjust if

necessary• Detain, isolate, and interview

witnesses and suspects• Coordinate team members

Steps for Crime Scene Investigation

Duties of the crime scene investigator3. Develop a plan and coordinate

investigation• Review existing security and adjust if

necessary• Detain, isolate, and interview witnesses

and suspects• Coordinate team members

Why must witnessesbe isolated?

Steps for Crime Scene Investigation

4. Observe and document the crime scenea. Conduct an initial walk-through

Identify transient evidence, Note all areas (such as exits and entrances) that need special attention,

Assess the need for specialty equipment or personnel,

Take initial photographs and documentation

Steps for Crime Scene Investigation

4. Observe and document the crime scene

b. Document the scene with photographs, videotapes, and/or sketches (more on this later!)

c. Collect and package evidence (more later!)

Steps for Crime Scene Investigation

4. Observe and document the crime scene

b. Document the scene with photographs, videotapes, and/or sketches (more on this later!)

c. Collect and package evidence (more later!)

5. Review the crime scene for missed evidence

Steps for Crime Scene Investigation

4. Observe and document the crime scene

b. Document the scene with photographs, videotapes, and/or sketches (more on this later!)

c. Collect and package evidence (more later!)

5. Review the crime scene for missed evidence

6. Maintain Chain of Custody ▪ Keep a record of every person who has had possession

of evidence at every time

Steps for Crime Scene Investigation

4. Observe and document the crime scene

b. Document the scene with photographs, videotapes, and/or sketches (more on this later!)

c. Collect and package evidence (more later!)

5. Review the crime scene for missed evidence

6. Maintain Chain of Custody ▪ Keep a record of every person who has had possession

of evidence at every time

Why is chain of custody important?

Steps for Crime Scene Investigation

You Do▪ Study the steps for 2 minutes▪ Put away notes▪ When I say go, rearrange the strips of

paper into the correct order

Evidence collection

One person designated as evidence collector Ensures that evidence is collected,

packaged, and marked in a consistent manner

Responsible that nothing is lost of contaminated

Transient evidence collected first

Evidence collection

Most pieces of evidence will go in two containers

Outer container will be labeled with:

Name of collector Date, time, and location of collection Type of evidence Chain of custody

Evidence collection

Controls (samples with known origin) are taken for comparisonExample:If a blood stain is found, blood would be collected from victims and suspects for comparison.

What other types of evidence might require controls?

Crime Scene Evaluation

We do – Evaluate Scenario A

Read the Crime Scene and Scenario A

Crime Scene Evaluation

We do – Evaluate Scenario A

Read the Crime Scene and Scenario A

As a class, discuss: What was done correctly?

What was done wrong, and how may those things hurt the investigation?

Crime Scene Evaluation

You do – In pairs, evaluate crime scene B and C

What was done correctly?

What was done wrong, and how may those things hurt the investigation?

Closure

4 (or 5 or 6) headed monster …

Homework

Document analysis lab! Major grade!

Exit Ticket

What, if anything, did we do right in analyzing the classroom crime scene?

What should we have done differently?