BLOODSTAIN PATTERNS
description
Transcript of BLOODSTAIN PATTERNS
![Page 1: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/1.jpg)
BLOODSTAIN PATTERNS
![Page 2: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/2.jpg)
BLOOD COMPONENTSPlasma• fluid portion of normal unclotted blood • red blood cells, white blood cells, and
platelets are suspended in it
![Page 3: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/3.jpg)
BLOOD COMPONENTS
Serum• liquid portion of clotted blood
![Page 4: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/4.jpg)
SURFACE TENSION OF BLOOD
• held together by strong cohesive molecular forces
• “outer skin”• Surface tension lightly less that that of water• Liquid mercury is about 10x greater • Blood does not fall in teardrop configuration
![Page 5: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/5.jpg)
SURFACE TENSION
• To create splatters, an external force must overcome surface tension of blood
![Page 6: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/6.jpg)
SURFACE TENSION
Surfaces• Generally, clean glass or smooth tile, very little
splatter• Rough texture, wood or concrete, significant
splatter
![Page 7: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/7.jpg)
GEOMETRY OF BLOODSTAIN
• Can determine direction of flight by examining edge characteristics
![Page 8: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/8.jpg)
GEOMETRY
Angle of impact 90 degrees • results in circular shape
![Page 9: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/9.jpg)
GEOMETRY
Angle of impact Less than 90 degrees
• Elongated
![Page 10: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/10.jpg)
![Page 11: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/11.jpg)
GEOMETRY
• If you measure width & length of an elliptical bloodstain you can calculate angle of impact
• Divide width by length • take sin-1 • gives angle of impact
![Page 12: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/12.jpg)
Geometry
• Once get angle of impact for each bloodstain• 3D origin may be determined
![Page 13: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/13.jpg)
DIRECTION OF TRAVEL
• Narrow end of elongated blood stain points in direction of travel
![Page 14: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/14.jpg)
![Page 15: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/15.jpg)
SPATTERED BLOOD
• random distribution of bloodstains that vary in size that may be produced buy a variety of mechanisms
![Page 16: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/16.jpg)
SPATTERED BLOODExamples:• Gunshot• Beating• Stabbing• power tools• Arterial• cast-off• passive
![Page 17: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/17.jpg)
SPATTERED BLOOD
• may allow determination of an area • or location of origin of blood source
![Page 18: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/18.jpg)
SPATTERED BLOOD
• If found on a suspect’s clothing, it may place that person at scene of violent altercation
![Page 19: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/19.jpg)
SPATTERED BLOOD
• May allow determination of mechanism by which pattern was created
![Page 20: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/20.jpg)
SIZE, QUANTITY AND DISTRIBUTION OF SPATTER DEPENDS ON
• Quantity of blood subjected to impact• Force of impact• Texture of surface impacted by blood
![Page 21: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/21.jpg)
GUNSHOT
• High Velocity Spatter• Misting effect• Varying sizes of impact spatters• Depend of caliber of weapon, location,
number of shots, etc.
![Page 22: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/22.jpg)
Gunshot
![Page 23: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/23.jpg)
EXAMPLE BACK SPATTER
![Page 24: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/24.jpg)
EXAMPLE GUNSHOT IMPACT SPATTER
![Page 25: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/25.jpg)
Beating and Stabbing Impact SpatterMedium Velocity Spatter
• Generally size range 1-3 mm in diameter
![Page 26: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/26.jpg)
Castoff Bloodstain PatternsLow Velocity Spatter
• Blood flung from object – such as bat or knife
![Page 27: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/27.jpg)
Passive BloodstainsLow Velocity
• Blood dripping from injured person
![Page 28: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/28.jpg)
What happens when blood hits blood?
• Drip patterns
![Page 29: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/29.jpg)
Large Volume Bloodstains
• Splashing and ricochet• Often from victim with large wound or
vomiting
![Page 30: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/30.jpg)
EXPIRATED BLOODSTAIN PATTERNS
• Blood accumulates in lungs, sinuses, airway passages of victim
• Forcefully expelled from living victim• Can look similar to other bloodstain patterns• can only be explained if victim has blood on
face
![Page 31: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/31.jpg)
ARTERIAL BLOODSTAIN PATTERNS
• Can be very large gushing or spurting patterns to very small spray types
![Page 32: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/32.jpg)
OTHER BLOODSTAIN PATTERNS
• Transfer bloodstain patterns• Altered bloodstains• Void areas or patterns
![Page 33: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/33.jpg)
INTERPRETATION OF BLOODSTAINS ON CLOTHING AND FOOTWEAR
• Whose blood is it?• How did it get there?
![Page 34: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/34.jpg)
LUMINOL
• Used for latent bloodstains at crime scene
![Page 35: BLOODSTAIN PATTERNS](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816624550346895dd97cc3/html5/thumbnails/35.jpg)
CHALLENGES
• Bloodstain pattern interpretation can be very complex
Need solid grasps of:• Mathematics• Physics• scientific method• practical experience