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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
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?