September 21-22, 2015 Forensic Science Pick-up: Turn-in: Signed Syllabus, lab safety contract. HW: Warm Up: Take 7 minutes to finish your vocabulary. Once you are done, show it to me to put in the gradebook.

7S’s of Crime Scene Investigation – Gallery Walk Make sure your notes are set up like this.

1. Secure the Scene First responding officer. Assist the victim(s)! Protect the crime scene (barrier tape) Search for and arrest suspect. Detain and separate witnesses. Note any changes made to the scene. Safety is the primary concern!

1. Securing the Crime Scene Secure the scene with physical barriers. One officer assigned to prevent entrance of unwanted personnel. Log kept of disturbances to scene. Anyone entering the scene will deposit and remove evidence. (Locard’s exchange principle)

2. Separating the Witnesses Questions to ask witnesses When did the crime occur? Who called in the crime? Who is the victim? Can the perpetrator be identified? What did you see happen? Where were you when you observed the crime scene?

3. Scan the Scene Scan to determine Where photos should be taken. Primary and secondary crime seen.

4. Seeing the Scene Detailed photography of the crime scene. Photos to take: Overall area Close-up photos

5. Sketching the Scene (Documentation) Detailed notes and sketches are vital to a crime scene! Three purposes of documentation: Record and document the location of evidence. Record the overall condition of the crime scene. To be used later for reconstruction purposes.

6. Searching for evidence After the original “walk-through”, the search of the scene begins. The goal of the crime scene search is to: Recognize, document, collect, and preserve physical evidence.

7. Secure the Evidence Temporary, fragile, or easily lost evidence should be collected first. Evidence placed in primary and secondary containers.

Crime Scene Investigation

Goal of Crime Scene Investigation Use evidence from the crime scene to figure out WHAT happened, HOW it happened, WHERE it happened, WHEN it happened, and WHO was involved.

Defining the Crime Scene - Purpose Defining the crime scene allows crime scene investigators to set parameters and limitations for the investigation.

Defining the Crime Scene - Location Any physical location where a crime occurred or is suspected of having occurred. The location where the ORIGINAL crime occurred. Any location where evidence is found. Ex. Where a body was dumped. Ex. Where bloody footprints found.

Primary vs. Secondary

Primary Crime Scene Primary vs. Secondary

Secondary Crime Scene Primary vs. Secondary

Physical Location of the Crime Scene Indoor, Outdoor, Vehicle, etc. Each type of physical location has specific requirements and limitations. Defining the Crime Scene – Physical Location

Defining the Crime Scene – Type of Crime Type of Crime Committed Homicide, robbery, sexual assault, etc.

Crime Scene Survey

Foldable!

The Linkage Theory The theory that believes if investigators can establish positive links between the physical evidence and/or victim, and/or crime scene, and/or suspect, then the case can be resolved. The more connections that can be made, the greater the likelihood the case can be resolved. Pro’s Builds a strong case. Con’s Allows for more assumption to be made.

The Transfer Theory The theory that believes that transfer evidence is created whenever two surfaces come into contact with one another. Matter is mutually exchanged across the contact barrier when two objects make contact. Pro’s Builds a strong case. Uses more science, and less “Assumptions”. Con’s May find many pieces of evidence that don’t seem to correspond to each other, or transfer theory. Leads to a dead end in the investigation.

The Transfer Theory Primary Transfer Where an exchange of substances is directly deposited. What happens when a homicide victim bleeds onto the floor. Secondary Transfer When the primary transfer is “picked up” from where it was originally deposited and moved to a new location. What happens when a suspect steps in the blood and leaves a bloody footprint.

Methods of Searching the Scene Line Method Grid Method Spiral Method Zone Method

Line Method Area is divided into strips, and CSIs and volunteers walk in a straight line to look for evidence. Used mostly for outdoor or large scenes.

Grid Method Area is divided into strips, and CSIs and volunteers walk in a straight line to look for evidence, then the area is searched perpendicular to the original lines. Used mostly for outdoor or large scenes. When looking for very small evidence: Bullet casing in outdoor scene.

Spiral Method Requires investigators to view the scene as a circle. May move inward or outward, in search of evidence. Best in scenes where there are no physical barriers. Be careful to not destroy evidence if there is more than one CSI.

Zone Method Crime scene is divided into logical zones that can be individually searched by team members. Most effective in houses or small scenes.

Important to remember during a search: View the crime scene as a whole. Keep an open mind. Look at the crime scene from different vantage points. Look for what is present as well as for what is missing. What type of scene is it? You only get ONE chance to search the scene. Do NOT alter the scene!

Scenario 1: A child is missing, and you and your team are called to search for a body in the area around the child’s house. What search method should you employ? Scenario 2: A crime was committed in the parking lot of the school. A bullet was found in the victim, which means there must be a bullet casing somewhere in the parking lot. What search method should you employ? Scenario 3: You arrive at a house where an apparent suicide was committed. You notice there is evidence scattered all over the house. What search method do you employ?