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8.4 Bloodstain Patterns

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					8.4 Bloodstain Patterns

         2.4.09
                 Blood Facts
   8% of total body weight
     Males 5-6 liters
     females 4-5 liters
     40% loss needed to cause death
               Important Factors
   Texture is very important
     Harder   the surface the less spatter
 Pointed end of a bloodstain always faces
  its direction of travel
 As angle decreases, the stain elongates
        Arrival At Crime Scene
 Ask yourself?
 Position of victim. (standing, sitting,
  lying)
  Evidence of a struggle. (blood smears,
  blood trails)
 Are stain patterns on a suspects clothing
  consistent with his reported actions?
  Are stain patterns on a victim or at a
  scene consistent with accounts given by
  witnesses or the suspect?
        Categories of Bloodstains
   Passive



   Transfer



   Projected
              Passive Bloodstains
   Passive Bloodstains
    are drops created or
    formed by the force of
    gravity acting alone.

   This category can be
    further subdivided to
    include;
        Drops
        Drip patterns
        Pools
        Clots
        Look at the three patterns,
        what can you me about the
               blood stain?




   Glass      linoleum flooring   wood or
                                   concrete
         Large Volumes of Blood
   "Dripped Blood"




   "Spilled Blood"
                  Projected Blood
   Created when an exposed
    blood source is subjected
    to an action or force,
    greater than the force of
    gravity
   The size, shape, and
    number of resulting stains
    will depend, primarily, on
    the amount of force
    utilized to strike the blood
    source.
                 Projected Blood
   Arterial Spurt / Gush
    Bloodstain pattern(s)
    resulting from blood
    exiting the body under
    pressure from a breached
    artery:
            Projected Blood
   Cast-off Stains
    Blood released or thrown from a
    blood-bearing object in motion:
                    Impact Spatter
 Low Velocity
  Gravitational pull up to 5
  feet/sec.
 Large stains 4 mm and greater
            Medium Velocity
 5 to 25 ft/sec
 1/ 4 mm in size
               High Velocity
 Force of a 100 and
  greater
 1 mm size and
  smaller
 Mist like appearance
        Direction of Blood Stains
   Blood Patterns

Measuring Bloodstains

				
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posted:11/18/2011
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