Module 10: Blood Spatter Analysis

Question 1

Blood Spatter Analysis

Answer 1

Analyze patterns of bloodstains

Question 2

What can be inferred from blood spatter?

Answer 2

• direction blood origin
• angle of the blood droplet on the surface
• location/position of victim at the time bloody wound as inflicted
• movement of bleeding individual
• minimum number of blows that struck a bleeding victim
• approximate location of an individual delivering blows that produced a bloodstain pattern

Question 3

Blood droplet

Answer 3

• spherical shape until contact on a surface
• same height, angle, surface = stains w/ same basic shape

Question 4

Types of Bloodstains

Answer 4

• passive bloodstains
• projected bloodstains
• expiration bloodstains
• transfer/ contact bloodstains
• impact bloodstains
• gunshot spatter
• forward spatter
• back spatter
• cast-off spatter

Question 5

Passive Bloodstains

Answer 5

• created by gravity
• pools of blood, as in tulo lang

Question 6

Projected Bloodstains

Answer 6

• force is applied to the blood source
• injury to a main artery/ heart

Question 7

True or False
Each large spurted stains does not correspond to a heart pump.

Answer 7

False

Question 8

Expiration bloodstains

Answer 8

• expelled from mouth or nose coz’ of internal injury

Question 9

Transfer or contact bloodstains

Answer 9

• bloody object/body comes in contact with a surface

Question 10

What is the most common bloodstain pattern?

Answer 10

Impact bloodstains

Question 11

Gunshot spatter

Answer 11

• characterized by both forward spatter (exit wound) and back spatter (entrance wound)

Question 12

Forward spatter

Answer 12

• projected outward
• away from the source

Question 13

Back spatter

Answer 13

• backward from the source
• talsik pabalik sa nanakit
• potentially deposited on the object or person who created the impact

Question 14

Some blood enters the gun muzzle due to back spatter

Answer 14

Drawback effect; indicates close-range firing

Question 15

Area of convergence

Answer 15

• location on a 2d plane from which the drops originated
• convergence of straight lines following the tails of ind. bloodstains.

Question 16

Area of origin

Answer 16

• area in 3d plane from which blood was projected
• position of the victim when the event happen
• closer to the surface -> clustered impact pattern

Question 17

True or False
Farther impact from the surface -> farther distribution and distance between drops.

Answer 17

True

Question 18

Cast-off spatter

Answer 18

• caused by swingin of blood-covered object
  -> fling of blood
• may show minimum number of blows

Question 19

True or False
The width of the cast-off pattern may help suggest the object that produced it.

Answer 19

True

Question 20

True or False
Cast-off pattern is not enough to suggest the direction of blow

Answer 20

False

Question 21

Factors affecting the shape of the droplet

Answer 21

• volume
• texture of the target surface
• angle of impact
• velocity
• height

Question 22

True or False
Bigger droplets, bigger bloodstains

Answer 22

True

Question 23

True or False
Harder and nonporous surface, more spatter

Answer 23

False. Less spatter

Question 24

What do you call the smaller bloodstain from the parent stain?

Answer 24

Satellite stain

Question 25

Shape of bloodstains found on rough surfaces.

Answer 25

Irregular shape with serrated edges, satellite stains

Question 26

True or False Exact velocity can be determined.

Answer 26

False

Question 26

Velocity of the droplet

Answer 26

- higher velocity of the force of impact on the source, higher velocity of the blood droplets - force and velocity increases, diameter decreases

Question 27

True or False Higher distance = larger diameter

Answer 27

True

Question 28

What is the maximum diameter?

Answer 28

7ft

Question 29

Challenges and Limitations

Answer 29

- contamination of crime scene can distort bloodstain patterns - environmental factors (airflow or temp) - interpretation varies