1. The Crime Scene

2. How Are Your Observation Skills?
This activity demonstrates our ability to remember details accurately.
Testimony about personal experience is frequently used during an investigation.
How accurately do people remember what they have seen?
What factors may play a role in what we can remember and describe about something we have witnessed?
Consider these questions as you do the following activity.

3. Directions:
Observe the picture for exactly 30 seconds. Look at everything you think might be important.
After 30 seconds, answer the questions
How observant were you? Compare your answers to the picture.
READY

5. Questions What time was it on the clock?
How many people were in the scene? How many males? females?
Describe the person at the front of the line. Was it a man or a woman? Was he or she wearing a hat? What kind of clothes was the person wearing? Could you tell how tall the person was? Did he or she have any distinguishing features?
What day of the month was it?
Did you notice anything unusual in the picture?

6. Did you know?
Eyewitness misidentification is the single greatest cause of wrongful convictions nationwide, playing a role in more than 75% of conviction overturned through DNA testing
Still, the criminal justice system relies on eyewitness identification and testimony for investigating and prosecuting crimes

7. Crime Scene Vocabulary
Crime Scene: Any physical location in which a crime has occurred or is suspected of having occurred Primary Crime Scene: The original location of a crime or accident

8. Vocabulary cont….
Suspect: Person thought to be capable of committing a crime Accomplice: Person associated with someone suspected of committing a crime Alibi: Statement of where a suspect was at the time of a crime Physical Evidence: Encompasses any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or crime and its perpetrator

9. Approaching a crime scene
First priority should be given to obtaining medical assistance for individuals in need of it and to arresting the perpetrator
Personal safety and the well being of victims
Preserve and isolate the crime scene
Record the crime scene

10. Crime scene personnel Police officers
Typically the first to arrive at a crime scene
They are responsible for securing the scene so no evidence is destroyed and detaining persons of interest in the crime

11. Personnel cont…. CSI unit
Documents the crime scene in detail and collects any physical evidence

12. Personnel cont…. District attorney
Often present to help determine if any search warrants are required to proceed and obtains those warrants from a judge

13. Personnel cont…. Medical examiner
(if a homicide) may or may not be present to determine a preliminary cause of death

14. Personnel cont…. Detectives
Interview witnesses and consult with the CSI unit
Investigate the crime by following leads provided by the witnesses and physical evidence

15. Crime Scene Protocol Step 1: Interview Step 2: Examine
The first step in investigating a crime scene is to interview the first officer at the scene or the victim to determine what allegedly happened, what crime took place, and how was the crime committed. This information may not be factual information but it will give the investigators a place to start.
Step 2: Examine
The second step in the investigation of a crime scene, which will help identify possible evidence, identify the point of entry and point of exit, and outline the general layout of the crime scene.
Step 3: Document
The third step in the protocol involves creating a pictorial record of the scene as well as a rough sketch to demonstrate the layout of the crime scene and to identify the exact position of the deceased victim or other evidence within the crime scene.
Step 4: Process
The crime scene technician will process the crime scene for evidence, both physical and testimonial evidence. It is the crime scene technicians responsibility to identify, evaluate and collect physical evidence from the crime scene for further analysis by a crime laboratory.

16. Recording the crime scene….Photographs
Evidence
Multiple views Entrances Exits Windows
Close ups Perspectives Multiple angles

17. Recording the crime scene….Sketch
A draft representation of all essential information and measurements at a crime scene
It shows all recovered items of physical evidence, as well as other important features of the crime scene

18. Recording the crime scene….Notes
Record of actual measurements of the scene, evidence and the relationship between them
Match to sketch
Use a key

19. Collecting Evidence Bag and Tag
Victims clothing
Fingernail scrapings
Head and pubic hairs
Blood
Hydrocarbons (arson)
Recovered bullets from the body and/or surrounding area
Hand swabs or washings from shooting victims

20. Documentation…Chain of custody
Description of item
Location in crime scene from which collected
Case number
Date/time collected
Signature of collector
They must identify
The time an item was discovered
By whom
How and whom it was packaged and marked

21. Rules for evidence collection
Maintain the physical integrity of a sample
Limit degradation (the act of degrading)
Prevent contamination
Chain of custody

22. The Seven S’s of Crime Scene Investigation
Secure the scene
Separate the witnesses
Scan the scene
Seeing the scene
Sketch the scene
Search for evidence
Secure the collected evidence

23. Forensic science services
Forensic pathology
Involves the investigation of unnatural, unexplained or violent deaths
Charged with determining the cause of death
May conduct autopsy which is a medical dissection and examination of a body in order to determine the cause of death

24. Forensic science services…cont
Forensic anthropology
Concerned with the identification and examination of human skeletal remains

25. Forensic science services…cont
Forensic entomology
The study of insects and their relation to a criminal investigation, commonly used to estimate time of death

26. Stages of death Rigor mortis
Results in the shortening of muscle tissue and the stiffening of body parts in the position at death (occurs in the first 24 hours and disappears within 36 hours)
Livor mortis
Results in the settling of blood in areas of the body closest to the ground (begins immediately on death and continues up to 12 hours)
Algor mortis
Results in the loss of heat by the body (general rule..the body loses heat by 1 to 1 ½ degrees Fahrenheit per hour until the body reaches the environmental temperature)