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Crime Scene Investigation and Evidence collection

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					Crime Scene
Investigation
and
Evidence
collection
                              UTube – Crime Scene Evidence
I. Introduction
    A. Crime Scene Investigation goal – to
        recognize, document and collect evidence
        at the scene of the crime  Engage – pg 22
II. Principle of Exchange
    A. Trace evidence – a physical transfer of different
        materials whenever people come in contact.
           *What type of materials might transfer?
      1.   Pet hair on clothes or rugs
      2.   Hair on your brush
      3.   Soil tracked into your house
      4.   A drop of blood on your t-shirt
      5.   A facial tissue
      6.   Paint chips
      7.   Fiber from clothing
B. Direct evidence – first hand observation such
   as eyewitness accounts or video cameras.
C. Circumstantial evidence – indirect evidence
   used to imply fact but doesn’t directly prove it.
   1. Physical – impressions such as fingerprints,
      footprints, shoe prints, tire impressions and
      tool marks.
   can also include fibers, weapons, bullets
   and shell casings




2. Biological – body fluids, hair, plant parts,
   and natural fibers.
      3. Trace evidence – hair on a brush, fingerprints
         on glass, blood drops on a shirt, soil tracked
         into a house from shoes and others.
                CSI Video Lab
III. Crime Scene Investigation Team   see explore pg. 24

   A. At the scene
      1. Police Officers
      2. Crime-scene Investigators – document the
         crime scene in detail and collect physical
         evidence
         a. Recorders
         b. Sketch artists
         c. Photographers
         d. Evidence collectors
       3. Medical examiner – determine cause of
          death
       4. Detectives – look for leads, interview
          witnesses and discuss evidence with crime
          scene investigators.
       5. Specialists – entomologists (insects), forensic
          scientists, forensic pathologists
IV. Seven S’s of Crime Scene Investigation
   A. Securing the Scene – first responder
       1.   safety of individuals
       2.   preservation of evidence
       3.   security log of all those that enter the scene
       4.   collects pertinent information
       5.   requests any additional needs required
               Protecting the Crime Scene Article and WS
B. Separating the Witnesses
  1. Do not allow them to talk to each other
  2. Ask the following questions:
     a.  When did the crime occur?
     b.  Who called in the crime?
     c.  Who is the victim?
     d.  Can the perpetrator be identified?
     e.  What did you see happen?
     f.  Where were you when you observed the
         crime scene?
C. Scanning the Scene         see pg. 25
   1. Primary crime scene
   2. Secondary crime scene
                          CSIBasics Video: Photographing
D. Seeing the Scene
    1. photographs of overall area and close-ups
        with and with out measuring device taken
    2. Triangulation of stationary objects include in
        photos as reference points.
    3. View of scene from several different angles
        and distances
    4. Close-ups of any evidence and bodies
E. Sketching the Scene
   1. Rough sketch – accurate noting the position
       of the body (if any) and any other evidence.
   2. all objects should be measured form 2
       immovable landmarks
   3. North and South labeled and scale of
       distance provided.
   4. Any other objects in vicinity of crime scene
F. Searching for Evidence
  1. Search Patterns
    a. Grid pattern – single investigator
b. Spiral – single investigator




c. Linear – group of investigators

                                  AKA Parallel
    d. Quadrant or Zone – multiple Investigators


                        Utube: What are the techniques used
                        to gather crime scene evidence?

                       Crime Scene Processing Article and WS
                       Crime Scene Sketch



                OJ Simpson Article


G. Securing and Collecting Evidence
  1. Needs to be properly packaged, sealed and
     labeled.
     a. Liquids and arson remains – stored in
        airtight, unbreakable containers.
   b. Biologicals – stored in breathable
      containers - allows it to dry out (mold).
     1. paper bindle (druggist’s fold) –
        packaged then placed in a plastic or
        paper container.
2. Chain of Custody and evidence log – must be
   attached to evidence container.
   a. info
      1. case #
      2. item inventory #
       3. description of evidence
       4. name of suspect
       5. name of victim
       6. date and time of recovery
            Handouts
      7. signature of person recovering
         evidence
      8. signature of
         witnesses present
         during
         collection.
3. Packaging Evidence
  a. Choose appropriate
     size of clean paper
  b. Crease the paper
  c. Place evidence in center
  d. Fold as shown
  e. Place inside plastic or
     paper evidence bag, fold
       f. place seal over folded edge of evidence
          bag
       g. Collector signs over folded
          edge
    4. Chain of Custody
V. Analyze the Evidence
    A. Forensic Lab
        1. processes all of the evidence – technicians
           are specialized and process 1 type of
           evidence
        2. Results sent to lead detective
VI. Crime Scene Reconstruction
    A. hypothesis of sequence of events beginning to
       end.
      B. Evidence is examined and compared with
         witnesses’ statements to determine reliability of
         their accounts.
     C. Determine how evidence fists into overall crime
         scenario.               Virtual Crime Scene WQ
VII. Staged Crime Scene – evidence doesn’t fit the
     testimony of witnesses.
     A. examples
         1. Arson – stages fire to cover another crime
         2. Suicide/Murder – murder victim is staged to
            look like a suicide.
         3. Burglary – staged to collect insurance
     B. Determination of Staged Scene
         1. Treat all death as homicides
         2. Do type of wounds found on victim match
            weapon employed?
   3. Could wounds e self-inflicted?
   4. Establish profile of victim; interview friends
      and family.
   5. Evaluate behavior of victim before event
   6. Evaluate behavior of suspects before event
   7. Corroborate statements with evidential fact
   8. Reconstruct the event
   9. Conduct all forensic examinations to
      determine the facts of the case
Crime Scene Investigator - http://www.yourdiscovery.com/crime/csi/


                 Don’t Touch The Evidence Lab

				
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posted:8/9/2011
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