1. Day 8 Crime Scene Investigation and Evidence Collection
Please take out your notes from chapter two and your objective sheet for unit one.
Look over the objectives for chapter 2 and compare with your notes. Be prepared to discuss.
What examples did you observe from the CSI pilot? What was false?
Forensic Science: Fundamentals & Investigations, Chapter 2

2. Scene Arrival What is going on Who is in charge Scene alterations FD
Ambulance
Witnesses
By standers
Photograph by C. Heidel
Forensic Science: Fundamentals & Investigations, Chapter 2

3. Scene Perimeter
Forensic Science: Fundamentals & Investigations, Chapter 2

4. Crime Scene Log Command personnel Limit the number of people at scene
Reports from ALL personnel at scene
Forensic Science: Fundamentals & Investigations, Chapter 2

5. Principle of Exchange
Dr. Edmond Locard, director of the world’s first forensic lab (1910, Lyon, France), established the idea of the exchange principle; namely that:
When a person comes in contact with an object or another person, a cross-transfer of physical material can occur.
Study of the material can determine the nature and duration of the transfer.
Forensic Science: Fundamentals & Investigations, Chapter 2

6. Transfer Theory in Practice
Links between Suspect and Victim
Link between Suspect and Scene
Link between Victim and Scene
Forensic Science: Fundamentals & Investigations, Chapter 2

7. Types of Evidence
Statements of a witness in court would be direct evidence.
Indirect or circumstantial evidence, such as a fingerprint (physical evidence) or blood or hairs (biological evidence), would imply something, and is called trace evidence.
Forensic Science: Fundamentals & Investigations, Chapter 2

8. Types of Evidence Evidence taken from a crime scene.
-Direct or circumstantial evidence?
-Physical or biological evidence?
-Class or individual evidence?
-Explain why this would be or would not be trace evidence.
Forensic Science: Fundamentals & Investigations, Chapter 2

9. Perishable Evidence example
Projectile
Forensic Science: Fundamentals & Investigations, Chapter 2

10. Value of Physical Evidence
Identifying
Class characteristics
Shoes
Tires
Firearms
Hair
Forensic Science: Fundamentals & Investigations, Chapter 2

11. Value of Physical Evidence
Individualization
Random process
Not predictable
Not controlled
Examples
Fingerprints- start in the womb
Variations on a tire / shoe
Firearms barrel
DNA
Forensic Science: Fundamentals & Investigations, Chapter 2

12. Crime Scene Processing See page 26 for sequence
Photographs
Video
Trace evidence
Scene search
Sketching
Evidence collection
Forensic Science: Fundamentals & Investigations, Chapter 2

13. Evidence collection-Bindle formation
Practice making a bindle to collect evidence on page 27.
Forensic Science: Fundamentals & Investigations, Chapter 2

14. Photographs Over all general scene Midrange Close up Scales
Directional arrows
Evidence markers
Forensic Science: Fundamentals & Investigations, Chapter 2

15. Overall Photograph
Forensic Science: Fundamentals & Investigations, Chapter 2

16. Crime Scene Photography
Mid-range
doorway/point of entry/exit)
evidence in original position
these are RELATIONSHIP photos
Forensic Science: Fundamentals & Investigations, Chapter 2

17. Mid-range Photograph
Forensic Science: Fundamentals & Investigations, Chapter 2

18. Mid-range Photograph
Forensic Science: Fundamentals & Investigations, Chapter 2

19. Crime Scene Photography
Close up photos of scene
good detailed shots of evidence or injuries
take a picture without a scale then with a scale
Forensic Science: Fundamentals & Investigations, Chapter 2

20. Close-up Photograph outdoor scene
Forensic Science: Fundamentals & Investigations, Chapter 2

21. Three Views Together
Forensic Science: Fundamentals & Investigations, Chapter 2

22. Sketching Measurements General sketch Complete diagram
Computer diagram
Forensic Science: Fundamentals & Investigations, Chapter 2

23. Simple Diagram Robbery Scene
Forensic Science: Fundamentals & Investigations, Chapter 2

24. The Crime Scene Investigation Team
Who is at the crime scene?
Police and possibly a district attorney.
Crime scene investigators.
Medical examiners.
Detectives.
Specialists.
Forensic Science: Fundamentals & Investigations, Chapter 2

25. The Seven S’s of Crime Scene Investigation
Secure the scene.
Separate the witnesses.
Scan the scene.
See to it that the crime scene examiners receive overall and close up photos with and without measuring rulers.
Sketch the scene.
Search for evidence.
Secure the collected evidence.
Forensic Science: Fundamentals & Investigations, Chapter 2

26. Packaging the evidence …let’s practice
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.
Forensic Science: Fundamentals & Investigations, Chapter 2

27. 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 (above, left).
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).
Forensic Science: Fundamentals & Investigations, Chapter 2

28. Analyze the Evidence
The facts of the case are determined when the forensic lab processes all the collected evidence.
The lab then sends the results to the lead detective who aims to see how it all fits into the crime scenario.
Forensic Science: Fundamentals & Investigations, Chapter 2

29. Analyze the Evidence 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.
Forensic Science: Fundamentals & Investigations, Chapter 2

30. Fourth Amendment-please write this down word for word on a separate sheet of paper. Lightly put your name on the back.
Forensic Science: Fundamentals & Investigations, Chapter 2

31. Crime Scene Reconstruction
Crime scene reconstruction involves:
forming a hypothesis
of the sequence of events
from before the crime was committed
through its commission.
Forensic Science: Fundamentals & Investigations, Chapter 2

32. Staged Crime Scenes
When the lab results do not match up with the testimony of witnesses, it can mean the crime was staged; common examples include:
Staging a fire—to cover bankruptcy.
Staging a suicide—to cover a murder.
Staging a burglary—to collect insurance money.
Forensic Science: Fundamentals & Investigations, Chapter 2

33. Staged Crime Scenes
To help determine whether a crime scene was staged, consider:
Whether the type of wound found on the victim matches the weapon employed.
Whether the wound could have been easily self-inflicted.
The mood and actions of the victim before the event.
The mood and actions of a suspect before the event.
Forensic Science: Fundamentals & Investigations, Chapter 2

34. Summary
Locard’s exchange principle: contact between people and objects can transfer material that can determine the nature and duration of the transfer.
Evidence can be direct or indirect (physical or biological traces).
A crime scene investigation team consists of police, detectives, crime scene investigators, medical investigators, and specialists.
The investigation consists of recognizing, documenting, and collecting evidence.
Forensic Science: Fundamentals & Investigations, Chapter 2

35. Summary
First responding officers identify the extent of the crime scene, secure it, and segregate witnesses.
Crime scene investigators document the crime scene.
Evidence must be collected, packaged, and labeled.
The evidence then is analyzed and interpreted to fit the crime scenario.
Forensic Science: Fundamentals & Investigations, Chapter 2

36. Review of Investigative Steps
Initial Response
Crime scene processing
Investigative stage
Identification and Arrest
Case preparation
Prosecution
Forensic Science: Fundamentals & Investigations, Chapter 2