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BLOOD SPATTER ANALYSIS Mrs. MacWilliams CSI Forensic Science **WARNING CONTAINS SOME GRAPHIC IMAGES.

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Presentation on theme: "BLOOD SPATTER ANALYSIS Mrs. MacWilliams CSI Forensic Science **WARNING CONTAINS SOME GRAPHIC IMAGES."— Presentation transcript:

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2 BLOOD SPATTER ANALYSIS Mrs. MacWilliams CSI Forensic Science **WARNING CONTAINS SOME GRAPHIC IMAGES

3 What does the abbreviation BPA represent? Bloodstain Pattern Analysis What can an investigator learn from the analysis of a blood spatter?  Type and velocity of weapon  Number of blows  Handedness of assailant (right or left-handed)  Position and movements of the victim and assailant during and after the attack  Which wounds were inflicted first  Type of injuries  How long ago the crime was committed  Whether death was immediate or delayed How does a blood droplet form? Click the image for an animation. Source:

4 Bloodstain Pattern Analysis Terms Spatter – Bloodstains created from the application of force to the area where the blood originated. Spatter – Bloodstains created from the application of force to the area where the blood originated. Origin/Source – The place from where the blood spatter came from or originated. Origin/Source – The place from where the blood spatter came from or originated. Angle of Impact – The angle at which a blood droplet strikes a surface. Angle of Impact – The angle at which a blood droplet strikes a surface. Parent Drop Spines Satellite Spatters Parent Drop – The droplet from which a satellite spatter originates. Satellite Spatters – Small drops of blood that break of from the parent spatter when the blood droplet hits a surface. Spines – The pointed edges of a stain that radiate out from the spatter; can help determine the direction from which the blood traveled.

5 Passive Bloodstains Passive Bloodstains Patterns created from the force of gravity Patterns created from the force of gravity Drop, series of drops, flow patterns, blood pools, etc. Drop, series of drops, flow patterns, blood pools, etc. Projected Bloodstains –Patterns that occur when a force is applied to the source of the blood –Includes low, medium, or high impact spatters, cast- off, arterial spurting, expiratory blood blown out of the nose, mouth, or wound. Transfer or Contact Bloodstains –These patterns are created when a wet, bloody object comes in contact with a target surface; may be used to identify an object or body part. –A wipe pattern is created from an object moving through a bloodstain, while a swipe pattern is created from an object leaving a bloodstain. Images from Types of Bloodstain Patterns

6 Blood Spatter Video Blood Spatter this week Blood Spatter this week

7 SOME OF THE BLOOD STAIN PATTERNS YOU ARE GOING TO CREATE THIS WEEK…

8 PASSIVE DROPS

9 ANGLE OF IMPACT

10 Directionality

11 Passive bloodstains

12 POOLS

13 CLOTS  A mass of blood and other contaminant s caused through clotting mechanisms

14 Arterial Gushing The large pattern of blood that is created when blood escapes an artery under pressure; the increase and decrease in blood pressure is apparent.

15 ARTERIAL SPURTS Large patterns created under pressure, but with less volume and usually more distinctive evidence of blood pressure rising and faling

16 Arterial Spurting

17 EXPIRATORY BLOOD Blood which is spattered onto a target, as a result of breathing, coughing, sneezing; typically this occurs when an injury is sustained to the throat, mouth or airway Many times, phlegm and mucous “bubbles” can be found within the blood spatter.

18 PROJECTED BLOOD (EX. Through a syringe)

19 Impact Site Usually the point on the body that recived the blow or applied force, from which the blood was shed Usually the point on the body that recived the blow or applied force, from which the blood was shed

20 Cast-Off Stains Blood that has been thrown from a SECONDARY object (weapon, hand, etc) onto a target other than the impact site

21 Low Velocity Blood traveling at 5 feet/sec or less Blood traveling at 5 feet/sec or less

22 MEDIUM VELOCITY Blood traveling at 5-25 feet/sec Blood traveling at 5-25 feet/sec

23 HIGH VELOCITY Blood traveling at 100 feet/sec or more Blood traveling at 100 feet/sec or more

24 High velocity spatter Gunshot wounds

25 TRANSFER PATTER Pattern created when a wet, bloody object comes in contact with a target surface, leaving a pattern, that has the features of the object making it useful for identifying the object

26 WIPE An altered bloodstain pattern resulting from an object moving through a preexisting wet bloodstain. An altered bloodstain pattern resulting from an object moving through a preexisting wet bloodstain. Imagine you have blood droplets on a tile floor and sometime after that the victim’s body is dragged across that floor. The original blood droplets may have a skeletonized apperance which may even indicate a minimum elapse time between the two events. skeletonized appearance which may even indicate a minimum elapsed time between the two events. The image below shows an existing mixed passive and impact spatter pattern that has had a clean cloth wiped across the surface from left to right. Imagine you have blood droplets on a tile floor and sometime after that the victim’s body is dragged across that floor. The original blood droplets may have a skeletonized apperance which may even indicate a minimum elapse time between the two events. skeletonized appearance which may even indicate a minimum elapsed time between the two events. The image below shows an existing mixed passive and impact spatter pattern that has had a clean cloth wiped across the surface from left to right.

27 WIPE The image below shows an existing mixed passive and impact spatter pattern that has had a clean cloth WIPED across the surface from left to right.

28 SWIPE A bloodstain pattern resulting from the transfer of blood from a blood-bearing surface onto another surface, with characteristics that indicate relative motion between the two surfaces. A bloodstain pattern resulting from the transfer of blood from a blood-bearing surface onto another surface, with characteristics that indicate relative motion between the two surfaces. In the picture below you will see a large swipe on a bathroom wall adjacent to the tub. There are also swipe stains on the edge of the tub and the heating vent on the floor. In the picture below you will see a large swipe on a bathroom wall adjacent to the tub. There are also swipe stains on the edge of the tub and the heating vent on the floor.

29 Skeletonized Stain Pattern left when an object moves through a partially dried stain, removing part of the blood but leaving the outline of the stain intact. Pattern left when an object moves through a partially dried stain, removing part of the blood but leaving the outline of the stain intact.

30 Shadowing/Ghosting/Void

31 SHADOWING/GHOSTING/VOID Pattern that helps to place an object or body in the scene; normally, the area in question lacks blood even though areas surrounding it show blood

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35 “STRINGING” WE WON’T DO THIS (IT IS VERY DIFFICULT) BUT VERY INTERESTING… WE WON’T DO THIS (IT IS VERY DIFFICULT) BUT VERY INTERESTING… Area of Convergence and Origin Using Stringing Video Area of Convergence and Origin Using Stringing Video Area of Convergence and Origin Using Stringing Video Area of Convergence and Origin Using Stringing Video

36 Determining Point of Origin

37 Point of Convergence: Identified by drawing a line through the long axis of a stain. Point of Convergence: Identified by drawing a line through the long axis of a stain. The point at which the stains converge is the blood spatter origin. The point at which the stains converge is the blood spatter origin.

38 Determining Area of Origin Area of Origin: The area in a 3 dimensional space from which the blood was projected Area of Origin: The area in a 3 dimensional space from which the blood was projected Shows position of victim and/or suspect Shows position of victim and/or suspect String method is commonly used to approximate the position of the area of origin using found angles of impact of individual stains in the pattern String method is commonly used to approximate the position of the area of origin using found angles of impact of individual stains in the pattern

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