1. Crime Scene Investigation

2. The Crime Scene Investigation Team
Who is at the crime scene?
Police and possibly a district attorney.
Crime scene investigators.
Medical examiners.
Detectives.
Specialists.

3. The Seven S’s of Crime Scene Investigation
Secure the scene.
Separate the witnesses.
Scan the scene.
See that photos are taken.
Sketch the scene.
Search for evidence.
Secure the collected evidence.

4. Secure the crime scene

5. Secure crime scene with tape

6. Separate the witnesses
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?

7. Scan the scene Determine primary and secondary crime scenes
Primary: where murder took place
Secondary: where corpse was found
Where should photos be taken?
Wear protective gear to prevent contamination of crime scene

8. Mark Evidence with Tents

9. See that photos are taken: Crime Scene Photography
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

10. Outside the Scene Exterior of building Arial photos
Pictures of all doors, windows and exits

11. Overall Shots – Outside the Scene
Outside science office
First shot entering door:
Exit (door)

12. 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

13. Overall Shots – Inside the Scene

14. Items of Evidence Take 2 shots:
Midrange shot: show how the item is related to its surroundings
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

15. Evidence: Knife (possible weapon)
Midrange Photo
Close-Up (with ruler)

16. Sketch crime scene 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

17. 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

18. Secure the collected evidence
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

19. Packaging Evidence Bindle: folded paper used to hold trace evidence
Crease a clean paper and place the evidence in the X position (as shown above).
Fold in the left and right sides, and then fold in the top and bottom.
Put the bindle into a plastic or paper evidence bag affixing a seal over the opening.
Write your name on the seal.

20. 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.
It is signed over to a technician in a lab for analysis who opens it, but not on the sealed edge.
After analysis, the technician puts it back in the evidence bag, seals it in another bag, and signs the evidence log (above, right).

21. (Simulated) Crime Scene Investigation

22. Crime Scene Personnel 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

23. Meanwhile….
…back at the lab…

24. Analyze the Evidence Process all collected evidence
Lab sends results to the lead detective, who fits the results into the crime scenario.

25. 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.

26. 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

27. 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.