Chapter 10

Front 1

• Location in 3D space that bloodproducing a bloodstain originated from• Determined by area of convergenceand angle of impact for each bloodstain• Shows position of victim or suspectwhen stain-producing event took place

Back 1

Area of orgin

Front 2

• Find area of convergence• Place pole or stand as axis comingfrom AC• Attach strings to droplets, usingprotractor line up with angle of impact, then attach to pole• View area of origin where stringsappear to meet• Approx. area of origin within errorof 2 ft.

Back 2

String method

Front 3

(Flows, Pools)

• Drops or large amounts of bloodflowing by pull of gravity• Active-blood from actively bleedingwound• Passive-blood deposited on surface(arterial spurt)

Back 3

Flows

Front 4

(Flows, Pools)

• Blood collects in a level &undisturbed place• Pool may be absorbed on porous surface• Drying time depends on environment• Skeletonization-edges of stain dryto the surface-remain even after it is disturbed

Back 4

Pools

Front 5

(Trail, Contract/Transfer, Void, Expirated patterns)

• Series of drops separate from otherpatterns formed by blood dripping off an object or injury• Show movement, lead to discardedweapon or provide ID

Back 5

Trail patterns

Front 6

(Trail, Contract/Transfer, Void, Expirated patterns)

• Simple transfer-object makes contactwith surface & is removed w/o movement• Movements across the surface- light& feathery• First transfer pattern darker

Back 6

Contract/Transfer patterns

Front 7

(Trail, Contract/Transfer, Void, Expirated patterns)

• Pattern created when a surfacecarrying wet blood comes in contact with a second surface• Fingerprints, handprints,footprints, footwear prints, tool prints, & fabric prints

Back 7

Contract/Transfer patterns

Front 8

(Trail, Contract/Transfer, Void, Expirated patterns)

• Object blocks deposition of bloodspatter onto a target surface• Blank space on surface gives clue tosize & shape of missing object• May find missing piece

Back 8

Void patterns

Front 9

(Trail, Contract/Transfer, Void, Expirated patterns)

• Blood expelled from the mouth ornose from internal injury• Under pressure = high-velocity • Presence of oxygen bubbles candifferentiate pattern• Lighter in color due to saliva

Back 9

Expirated Blood Patterns

Front 10

• Back spatter that strikes gunman• May enter the gun muzzle• Blow-back spatter on weapon’s muzzleconsistent with weapon being close to victim at time of firingCast-off Spatter

Back 10

Drawback effect

Front 11

• the study of blood patterns todetermine several different factors at an incident scene.

Back 11

Blood stain pattern analysis

Front 12

What can Blood stain pattern analysis determine?

Back 12

Surface texture

Front 13

(Medium, High, Low)

• Small drops 1 to 3 mm• Blunt force trauma • 5 to 25 ft/s

Back 13

Medium velocity

Front 14

(Medium, High, Low)

• Diameter < 1 mm• 100 ft/s or faster• Gunshot wounds or explosions• Small droplets might not travel far

Back 14

High velocity

Front 15

(Medium, High, Low)

• largeseparate or compounded drops-diameter 3 mm or more• Minimal forceor object dropping & splashing from blood pool• Velocity <5 ft./s

Back 15

Low velocity

Front 16

Forward or back?

outward & away from source

Back 16

Forward

Front 17

Forward or back?

backward from source

Back 17

back

Front 18

Would this be on a (1) Harder & nonporous surfaces or (2) Rough surfaces?

less spatter

Back 18

Harder

Front 19

Would this be on a (1) Harder & nonporous surfaces or (2) Rough surfaces?

irregularly shaped stains with serrated edges

Back 19

rough

Front 20

• small droplets around perimeter fromblood impacting surface

Back 20

Satellite spatter

Front 21

(90 degrees, larger angles or smaller angles)

circular shape, no tail or buildup

Back 21

90 degrees

Front 22

(90 degrees, larger angles or smaller angles)

buildup of blood

Back 22

larger

Front 23

(90 degrees, larger angles or smaller angles)

longer tails

Back 23

smaller

Front 24

acute angle formedbetween path of blood & surface contacted

Back 24

angle of impact

Front 25

(Impact, gunshot, cast off, arterial spatter)

pattern produced whenobject makes forceful contact with blood source-projects droplets outward fromsource

Back 25

Impact spatter

Front 26

(Impact, gunshot, cast off, arterial spatter)

• Forward spatter from exit wound& back spatter from from entrance wound• Pattern of very fine high-velocityspatter affected by location of injury, size of wound,distance between victim& muzzle

Back 26

gunshot spatter

Front 27

(Impact, gunshot, cast off, arterial spatter)

• Pattern created when blood-coveredobject flings blood in an arc onto nearby surface• Movement of bloody fist or weaponbetween blows• Arc may suggest kind of object

Back 27

Cast off spatter

Front 28

(Impact, gunshot, cast off, arterial spatter)

• May indicate direction right to leftor left to right• May indicate number of blows• First blow causes blood to pool• ME best person to estimate number ofblows

Back 28

Cast off spatter

Front 29

(Impact, gunshot, cast off, arterial spatter)

• Victim suffers an injury to mainartery or heart• Blood spurts out from pumping heart• Radial spikes, satellite spikes orflow patterns may be evident because of large blood volume• Stains may show movement• Arterial blood brighter red in color

Back 29

Arterial Spray Spatter

Front 30

(Wipe, Swipe)

• created when an object moves throughan existing stain, removing and/or altering its appearance.

Back 30

Wipe

Front 31

(Wipe, Swipe)

• The transfer of blood from a movingsource onto an unstained surface. Direction of travel may be determined by thefeathered edge.

Back 31

Swipe