watch me!
August 19, 2014
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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
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Crime scene – anywhere evidence may be
located
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Primary crime scene – the place where the
crime was committed
(example: where someone was murdered)
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Secondary crime scene – another place
related to a crime
(example: where the body was dumped)
First responders – the first people at a crime scene,
usually police, firemen, or medical personnel.
First responders – the first people at a crime scene,
usually police, firemen, or medical personnel.
Duties of the first responders
1. 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?
First responders – the first people at a crime scene,
usually police, firemen, or medical personnel.
Duties of the first responders
1. Scene management
 Establish scene diameters
 Identify potential hazards
 Assist injured persons
 Search for and arrest suspect, if possible
Duties of the first responders
2.
Secure the crime scene – prevent access by
unauthorized personnel
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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
Duties of the first responders
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May use multilevel security
Level 1: Restriction of general public;
medial allowed
Level 2: Offical business only;
command center here
Level 3: Highest security
Discuss with a partner:
What important principle of forensics is related to the
need to secure the crime scene?
Duties of the first responders
What is the benefit of multi-level security?
▪
May use multilevel security
Level 1: Restriction of general public;
medial allowed
Level 2: Offical business only;
command center here
Level 3: Highest security
Duties of the crime scene investigator
3. Develop a plan and coordinate investigation
• Review existing security and adjust if necessary
• Detain, isolate, and interview witnesses and
suspects
• Coordinate team
members
Duties of the crime scene investigator
3. 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 witnesses
be isolated?
4.
Observe and document the crime scene
a. 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
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!)
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
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
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Keep a record of every person who has had possession
of evidence at every time
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
Why is chain of custody important?
6.
Maintain Chain of Custody
▪
Keep a record of every person who has had possession
of evidence at every time
You Do
▪ Study the steps for 2 minutes
▪ Put away notes
▪ When I say go, rearrange the strips of paper into
the correct order
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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
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Transient
evidence
collected first
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Most pieces of evidence will go in two
containers
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Outer container will be
labeled with:
 Name of collector
 Date, time, and location of
collection
 Type of evidence
 Chain of custody
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Controls (samples with known origin) are
taken for comparison
Example:
If a blood stain is found, blood would be collected
from victims and suspects for comparison.
What other types of evidence might require
controls?
We do – Evaluate Scenario A
Read the Crime Scene and Scenario A
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?
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?
4 (or 5 or 6) headed monster …
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Document analysis lab!
Major grade!
What, if anything, did we do right in analyzing
the classroom crime scene?
What should we have done differently?