BLOOD BLOOD SPATTER SPATTER ANALYSISANALYSIS

Mrs. MacWilliamsCSI Forensic Science

**WARNING CONTAINS SOME GRAPHIC IMAGES

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: http://science.howstuffworks.com/bloodstain-pattern-analysis1.htm

Bloodstain Pattern Analysis TermsBloodstain Pattern Analysis Terms

• Spatter – Bloodstains created from the application of force to the Spatter – Bloodstains created from the application of force to the area where the blood originated.area where the blood originated.

• Origin/Source – The place from where the blood spatter came from Origin/Source – The place from where the blood spatter came from or originated.or originated.

• Angle of Impact – The angle at which a blood droplet strikes a Angle of Impact – The angle at which a blood droplet strikes a surface.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.

• Passive BloodstainsPassive Bloodstains• Patterns created from the force of gravityPatterns 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 http://www.bloodspatter.com/BPATutorial.htm

Types of Bloodstain PatternsTypes of Bloodstain Patterns

Blood Spatter VideoBlood Spatter Video

Blood Spatter this week

SOME OF THE BLOOD SOME OF THE BLOOD STAIN PATTERNS YOU ARE STAIN PATTERNS YOU ARE

GOING TO CREATE THIS GOING TO CREATE THIS WEEK…WEEK…

PASSIVE DROPSPASSIVE DROPS

ANGLE OF IMPACTANGLE OF IMPACT

DirectionalityDirectionality

Passive bloodstainsPassive bloodstains

POOLSPOOLS

CLOTSCLOTS

A mass of blood and other contaminants caused through clotting mechanisms

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

ARTERIAL SPURTSARTERIAL SPURTSLarge patterns created under pressure, but with less volume and usually more distinctive evidence of blood pressure rising and faling

Arterial SpurtingArterial Spurting

EXPIRATORY BLOODEXPIRATORY BLOODBlood 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.

PROJECTED BLOODPROJECTED BLOOD(EX. Through a syringe)(EX. Through a syringe)

Impact SiteImpact Site Usually the point on the body that recived Usually the point on the body that recived

the blow or applied force, from which the the blow or applied force, from which the blood was shedblood was shed

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

Low VelocityLow Velocity Blood traveling at 5 feet/sec or lessBlood traveling at 5 feet/sec or less

MEDIUM VELOCITYMEDIUM VELOCITY Blood traveling at 5-25 feet/secBlood traveling at 5-25 feet/sec

HIGH VELOCITYHIGH VELOCITY Blood traveling at 100 feet/sec or Blood traveling at 100 feet/sec or

moremore

High velocity spatterHigh velocity spatterGunshot wounds

TRANSFER PATTERTRANSFER PATTERPattern 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

WIPEWIPE An altered bloodstain pattern resulting from an object An altered bloodstain pattern resulting from an object

moving through a preexisting wet bloodstain.moving through a preexisting wet bloodstain. Imagine you have blood droplets on a tile floor and Imagine you have blood droplets on a tile floor and

sometime after that the victim’s body is dragged sometime after that the victim’s body is dragged across that floor. The original blood droplets may across that floor. The original blood droplets may have a skeletonized apperance which may even have a skeletonized apperance which may even indicate a minimum elapse time between the two indicate a minimum elapse time between the two events. events. skeletonized appearance which may even skeletonized appearance which may even indicate a minimum elapsed time between the two indicate a minimum elapsed time between the two events.  The image below shows an existing mixed events.  The image below shows an existing mixed passive and impact spatter pattern that has had a passive and impact spatter pattern that has had a clean cloth wiped across the surface from left to right.clean cloth wiped across the surface from left to right.

WIPEWIPEThe 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.

SWIPESWIPE A bloodstain pattern resulting from the transfer A bloodstain pattern resulting from the transfer

of blood from a blood-bearing surface onto of blood from a blood-bearing surface onto another surface, with characteristics that indicate another surface, with characteristics that indicate relative motion between the two surfaces. relative motion between the two surfaces. 

In the picture below you will see a large swipe on In the picture below you will see a large swipe on a bathroom wall adjacent to the tub. There are a bathroom wall adjacent to the tub. There are also swipe stains on the edge of the tub and the also swipe stains on the edge of the tub and the heating vent on the floor. heating vent on the floor.

Skeletonized StainSkeletonized Stain Pattern left when Pattern left when

an object moves an object moves through a partially through a partially dried stain, dried stain, removing part of removing part of the blood but the blood but leaving the outline leaving the outline of the stain intact.of the stain intact.

Shadowing/Ghosting/VoidShadowing/Ghosting/Void

SHADOWING/GHOSTING/SHADOWING/GHOSTING/VOIDVOID

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

““STRINGING”STRINGING”

WE WON’T DO THIS (IT IS VERY WE WON’T DO THIS (IT IS VERY DIFFICULT) BUT VERY INTERESTING…DIFFICULT) BUT VERY INTERESTING…

Area of Convergence and Origin Using Stringing Video

Determining Point of OriginDetermining Point of Origin

Determining Point of OriginDetermining Point of Origin

Point of Point of Convergence: Convergence: Identified by Identified by drawing a line drawing a line through the long through the long axis of a stain.axis of a stain.

The point at which The point at which the stains converge the stains converge is the blood spatter is the blood spatter origin.origin.

Determining Area of OriginDetermining Area of Origin Area of Origin: Area of Origin: The area The area

in a 3 dimensional space in a 3 dimensional space from which the blood was from which the blood was projectedprojected

Shows position of victim Shows position of victim and/or suspectand/or suspect

String method is commonly String method is commonly used to approximate the used to approximate the position of the area of position of the area of origin using found angles of origin using found angles of impact of individual stains impact of individual stains in the patternin the pattern