Crime Scene Investigation
The Crime Scene
Investigation Team
Who is at the crime scene?
 Police and possibly a district attorney.
 Crime scene investigators.
 Medical examiners.
 Detectives.
 Specialists.
The Seven S’s of Crime Scene
Investigation
1.
2.
3.
4.
5.
6.
7.
Secure the scene.
Separate the witnesses.
Scan the scene.
See that photos are taken.
Sketch the scene.
Search for evidence.
Secure the collected evidence.
Secure the crime scene
Secure crime scene with tape
Separate the witnesses

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Do not allow witnesses to talk to each other
Witness accounts will be compared
Avoid witnesses working together to create a
story
Asked: who, what, where?
Scan the scene

Determine primary and secondary crime
scenes
–
–
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Primary: where murder took place
Secondary: where corpse was found
Where should photos be taken?
Wear protective gear to prevent
contamination of crime scene
Mark Evidence with Tents
See that photos are taken:
Crime Scene Photography

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Show the scene exactly as it was when you
first saw it
If something was moved before you arrived,
don’t try to reconstruct the scene – just take
the pictures the way you see it
Be careful not to destroy any evidence while
taking photos
Outside the Scene
Exterior of building
 Arial photos
 Pictures of all doors, windows and exits

Overall Shots – Outside the Scene
Outside
science office
First shot entering door:
Exit (door)
Inside the Scene

Begin with a view of the entrance
 Then photograph the scene as it appears
when you first step into the room
 Next, move around the room to get
photographs of all the walls (also show
positions of any possible pieces of evidence)
 Photos of other rooms connect with crime
scene
Overall Shots – Inside the Scene
Items of Evidence
Take 2 shots:
1. Midrange shot: show how the item is
related to its surroundings
2. Close-up: bring out details of item


Take 2 close-up shots if marking or measuring
device is used
One shot without device, one shot with device
Evidence: Knife (possible weapon)
Midrange Photo
Close-Up (with ruler)
Sketch crime scene


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Make accurate rough
sketch
Note direction (N) and
scale of distance
Include relevant objects
(body, doors, windows,
furniture, immovable
landmarks)
Make final copy (on
computer) for court
N
Search for evidence



Grid, strip or lane, spiral search pattern
Use flashlight to find hair and fibers
Use forceps, vacuum cleaner to collect evidence
Grid
Strip or Lane
Spiral
Secure the collected evidence
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Properly package, seal, and label ALL
evidence!
Liquid: airtight, unbreakable containers
Wet items (biological): dry out in breathable
container
Dry item: bindle  plastic or paper container
Seal with tape and labeled with pertinent info
Packaging Evidence
Bindle: folded paper used to hold trace evidence
1. Crease a clean paper and place
the evidence in the X position (as
shown above).
2. Fold in the left and right sides, and
then fold in the top and bottom.
3. Put the bindle into a plastic or
paper evidence bag affixing a seal
over the opening.
4. Write your name on the seal.
Chain of Custody
In order to present credible evidence in
court, a chain of custody log is essential.
A person bags the evidence, marks it for
identification, seals it, and signs it across the sealed
edge.
2. It is signed over to a technician in a lab for analysis
who opens it, but not on the sealed edge.
3. After analysis, the technician puts it back in the
evidence bag, seals it in another bag, and signs the
evidence log (above, right).
1.
(Simulated) Crime Scene
Investigation
Crime Scene Personnel
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•
•
•
•
First Responder
Recorder
Sketch Artist
Photographer
2 Evidence Collectors
• Duties:
– Read and complete
your specific checklist
– Wear gloves to handle
evidence
– Evidence logs filled
out by Recorder and
Evidence Collector
Meanwhile….
…back at the lab…
Analyze the Evidence
Process all collected evidence
Lab sends results to the lead
detective, who fits the results into the
crime scenario.
The lab results can:
Show how reliable are any witness
accounts.
Establish the identity of suspects or
victims.
Show suspects to be innocent or
link them with a scene or victim.
Staged Crime Scenes
What if the lab results do not match up
with the testimony of witnesses? Was it
staged?
Common situations:
Arson — to cover bankruptcy or murder
Suicide — to cover a murder
Burglary — to collect insurance money
To help determine whether a crime
scene was staged, consider:
Does wound match weapon?
Could wounds be easily self-inflicted?
Profile victim
The mood and actions of the victim
before the event.
The mood and actions of a suspect
before the event.
Corroborate statements with evidence
and facts.