Forensic Science physical evidence and the crime scene .._1_

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Forensic Science physical evidence and the crime scene .._1_ Powered By Docstoc
					  SEPTEMBER 24, 2012
  WARM-UP:
  STANDARD: SFS1C DETERMINE THE PROPER
  TECHNIQUES TO SEARCH, ISOLATE, COLLECT AND R
  PHYSICAL AND TRACE EVIDENCE.
EQ: What is the process by which physical
evidence is collected?
Write the following questions:
1. What was the name of the missing teen?
2. What were the circumstances surrounding her
disappearance?
3. Who is the lead suspect in this crime?
FORENSIC SCIENCE

PHYSICAL EVIDENCE AND THE CRIME SCENE
CHAPTER 2
PHYSICAL EVIDENCE

Any object that can
 establish that a crime
 has been committed or
 can link a crime and its
 victim or its perpetrator

Presence must be
 recognized at the crime
 scene.
SECURING AND ISOLATING THE CRIME SCENE

                  The first officer on the
                   scene must obtain
                   medical help for any
                   injured parties and
                   arrest the perpetrator,
                   if possible.

                  The crime scene must
                   be isolated and
                   protected as much as
                   possible.
Unauthorized personnel
 should be kept away from
 the crime scene.

The lead investigator
 must set the boundaries
 and determine the entry
 and exit pathways.
RECORD THE SCENE
The crime scene needs to
 be permanently recorded
 in the original state.
  Needed for future reference
  Needed for court

3 methods
  1. Photography
  2. Sketches
  3. Notes
1. PHOTOGRAPHY
                  must be unaltered, objects
                   cannot be moved
                    If something is removed
                       from the scene, it is noted
                       but is not reintroduced.
                  scene photographed as
                   completely as possible,
                   including surrounding areas,
                   from all angles
                  physical evidence
                   photographed to show location
                   and position, close-ups taken
                   to show detail, ruler can be
                   added to show scale
Crime Scene Investigation
• Photographing the Crime Scene:
1. PHOTOGRAPHY (CONT.)
                 digital pictures can be
                  altered, sometimes not
                  acceptable in court, but
                  can be joined to show 3D
                  picture of scene

                 Videotaping can be used
                  in same manner of digital
                  camera, can also capture
                  narration of scene
2. SKETCHES
 Rough sketch

  contains actual dimensions of
   the scene, accurate
   measurements made with tape
   measure

  shows location of objects
   deemed of value to scene

  basic diagram of scene

  compass added to show north

  legend or list of items added
2. SKETCHES (CONT.)
Finished sketch

Must contain
 information from
 rough sketch

More precise, neater

Can be made with
 computer
     Did you know...

A cat’s urine glows under a blacklight?



                         111,111,111 x 111,111,111 =
                         12,345,678,987,654,321?




 Months that start with a Sunday will
 always have a Friday the 13th?
3. NOTES
            Must include detailed
             written description of
             the scene with the
             location of items of
             physical evidence
             recovered

            Must also identify the
             time an item was
             discovered, by whom,
             how and by whom it was
             packaged and marked,
             and the disposition of
             the item after it was
             collected
3. NOTES (CONT.)
 May be only source of information when
  preparing for court case years later, should
  be very detailed

 Tape recordings and videotaping may be
  helpful at scene, used to make notes later
DEALING WITH
  PHYSICAL
  EVIDENCE
Crime Scene Investigation
• Uses and Information from Physical Evidence :


            Victim                                  Suspect




                           Physical Evidence




             Object                               Scene
DEALING WITH PHYSICAL EVIDENCE
 After the lead detective does
  the preliminary walk-through,
  a more thorough search for
  physical evidence begins.

 Once found, evidence must
  be collected and stored in a
  way that preserves its
  integrity for forensic
  comparison and analysis.

 The chain of custody has to
  be maintained at all times.
CONDUCT A SYSTEMATIC SEARCH FOR EVIDENCE

One person should
 supervise and
 coordinate the collection
 of evidence.
May divide the area into
 segments and collect
 evidence individually, or
 move from the outside
 in to the center.
Search area must include
 probable points of entry and
 exit used by the criminals.

What to search for will be
 determined by the nature of
 the crime.

Evidence collector ensures that
 evidence is collected, packaged,
 marked, sealed, and preserved
 in a consistent manner
How many people
 supervise and
 coordinate the
  collection of
   evidence?
COLLECT PHYSICAL EVIDENCE
 Take all clothing worn by participants in a crime. Each
  piece should be packaged carefully and separately.

 ITEMS OBTAINED FROM THE BODY & SENT TO THE LAB:
 1. Victim’s Clothing
 2. Fingernail Scrapings
 3. Head and pubic hairs
 4. Blood
 5. Vaginal, anal, oral swabs (sex-related crimes)
 6. Recovered bullets from the body
 7. Hand swabs from shooting victims (gunshot residue
  analysis)
Critical areas of a crime
 should be vacuumed, and
 sweepings from different
 areas should be packaged
 separately.

Fingernail scrapings should
 be taken from individuals
 who may have been in
 contact with other involved
 individuals.
OCTOBER 16, 2012
WARM-UP:
STANDARD: SFS1c Determine the proper
 techniques to search, isolate, collect and record
 physical and trace evidence.
EQ: Can you determine whether or not evidence
 was collected, labeled and sealed properly?

Write down each sentence and fill-in-the-blank.
           judge
1.The __________ ultimately decides the
 significance of physical evidence in a trial.
2. If a crime takes place outside and it rains, shoe
 prints will probably ___be/not be___ collected.
3. Blood soiled items should always be air-dried
                         p aper bag
 and collected in a(n)_____________.
           PACKAGING
                       Forceps and similar tools
                        may have to be used to
THE CRIME SCENE
THE CRIME SCENE



                        pick up small items.

                       Unbreakable plastic pill
                        bottles with pressure lids
                        are excellent containers for
                        hairs, glass, fibers, and
                        various other kinds of
                        small or trace evidence.
 Manila envelopes,screw-
  cap glass vials, or
  cardboard pillboxes are
  adequate containers for
  most trace evidence
  encountered at crime
  sites.

 Ordinary mailing
  envelopes should not be
  used as evidence
  containers because
  powders and fine
  particles will leak out of
  their corners.
           PACKAGING
THE CRIME SCENE
THE CRIME SCENE




                       Small amounts of
                        trace evidence can
                        also be conveniently
                        packaged in a
                        carefully folded paper,
                        using what is known
                        as a “druggist fold.”
If bloodstained
 materials are stored in
 airtight containers,
 moisture collecting
 inside cause the growth
 of mold, which can
 destroy the evidential
 value of blood.

In these instances,
 wrapping paper, manila
 envelopes, or paper
 bags are recommended
 packaging materials.
           OBTAINING REFERENCE SAMPLES

                        Standard/Reference Sample—
                         Physical evidence whose origin is
THE CRIME SCENE
THE CRIME SCENE




                         known, such as blood or hair from
                         a suspect, that can be compared to
                         crime-scene evidence.


                        The examination of evidence,
                         whether it is soil, blood, glass, hair,
                         fibers, and so on, often requires
                         comparison with a known
                         standard/reference sample.
Although most investigators have little difficulty
 recognizing and collecting relevant crime-scene
 evidence, few seem aware of the necessity and
 importance of providing the crime lab with a
 thorough sampling of standard/reference
 materials.
   PHYSICAL          COLLECTION               WHY?
   EVIDENCE          CONTAINER
victim’s clothing
                      Paper bags
Blood-stained       Wrapping paper, manilla
                    envelopes, or paper
shirt               bags
                    Plastic pill bottles or
hair                druggist fold

soil
Charred debris
                       Air tight container


glass                 Plastic pill bottles

drugs                Sealed plastic bag
BASICS OF EVIDENCE COLLECTION:

1. Glass and metal should be collected in rigid
 containers
2. Hair, fibers, and small evidence should be
 collected in manila envelopes or sealed in plastic
 if there are no fluids present.
3. Bodily fluids should be air-dried and collected in
 porous containers such as paper bags.
4. Arson evidence (charred debris) should be
 collected in an air tight container to prevent
 evaporatioin.
LABELING & SEALING THE CONTAINER:
1. Each container should be labeled with:
     a. Name of collector
     b. Date of collection
     c. Time of collection
     d. Description of evidence
2. A seal should be placed across the opening of
   the container with the initials of the collector n
   and the date.
EVIDENCE
   LAB
            CHAPTER 2 NOTEBOOK CHECK
 1. Ch 2 Reading Guide
 2. Value of Evidence Video Questions
 3. Crime Scene Investigation Notes
 4. Ch 2 Review Questions (1-26)
 5. Crime Scene Lab- “Don’t Touch the Evidence”
 6. Collecting Physical Evidence Notes
 7. Physical Evidence Collection Chart
 8. Jonbenét Ramsey Documentary (30 Notes)
 9. Evidence Lab
 10. Autopsy & Death Notes
 11. Autopsy Web Quest
 12. Autopsy of a Banana

				
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