Chapter 11 - Applying Blood Stain Pattern Analysis in the Crime Scene

Question 1

Describe the basic steps used to conduct a blood stain pattern analysis.

Answer 1

?

Question 2

What are the two primary categories in the bloodstain pattern taxonomy, and what distinguishes one from the other?

Answer 2

· spatter stains

· nonspatter stains

Question 3

What is the general rule regarding the relationship of a bloodstain’s shape and impact angle?

Answer 3

The more round the shape of the stain, the closer it is to 90°. The more elliptical the shape of the stain, the lower the degree of angle of impact.

Question 4

What is meant by stain directionality, and how is it determined?

Answer 4

Size and shape of the blood drop, including any tails, scalloping and accompanying drops.

Question 5

How are point of convergence and area of origin used to evaluate an impact spatter pattern?

Answer 5

Provides an area where the blood originated from on a 3D plane.

Question 6

What are the three key elements considered when viewing and evaluating a luminol reaction?

Answer 6

·Color
·duration
·intensity

Question 7

In your own words describe the concept behind the pattern diversity principle.

Answer 7

“The variations in combinations of blood volumes and forces acting on those volumes lead to a recognizable classes of pattern.” Pg 332

Question 8

How is infrared photography helpful in documenting blood stain patterns on some services?

Answer 8

It helps to visualize bloodstain patterns by eliminating background patterns and creating greater contrast between the bloodstain and the substrate it’s on.

Question 9

What is meant by a complex pattern?

Answer 9

A group of multiple pattern types in one larger pattern.

Question 10

Why are close-up detail and close-up photographs so important in documenting bloodstain patterns?

Answer 10

Correlation to location in the scene as well as scene reconstruction.

Question 11

What are the three underlying principles of bloodstain pattern analysis?

Answer 11

·the pattern diversity principle (bloodstain patterns)
· the principle of stain shape and vector correlation (directionality & angle of impact)
· the physically altered bloodstain (PAB) principal (altered bloodstain patterns)

Question 12

What are the six primary bloodstain mechanism categories (types)?

Answer 12

· impact/expirated patterns
· projection/spurting patterns
·cast-off patterns
·flows/pooling/saturation patterns
·smear/wipe/swipe patterns
·drip/drip trail/blood-into-blood patterns