Chapter 10: Bloodstain Pattern Analysis

bloodstain patterns

Violent contact between individuals at a crime scene frequently produces bleeding and results in the formation of [BLANK].

control experiments

The proper interpretation of bloodstain patterns necessitates carefully planned [BLANK] using surface materials comparable to those found at the crime scene.

victims; suspects

Bloodstain patterns may convey to the analyst the location and movements of [BLANK] or [BLANK] during the commission of a crime.

True

True or False: Harder and less porous surfaces result in less spatter, whereas rough surfaces result in stains with more spatter and serrated edges.

increases

Generally, bloodstain diameter (increases/decreases) with height.

directionally; angle of impact

The [BLANK] and [BLANK] of blood striking an object may be discerned by the stain’s shape.

circular

A drop o blood that strikes a surface at an angle of impact of approximately 90 degrees will be close to (elliptical, circular) in shape.

width; length

The angle of impact of an individual bloodstain can be estimated using the ratio of [BLANK] divided by [BLANK].

impact spatter

[BLANK] is the most common type of blood spatter found at a crime scene and is produced when an object forcefully contacts a source of blood.

False

True or False: Forward spatter consists of the blood projected backward from the source, and back spatter is projected outward and away from the source.

low velocity; medium velocity; high velocity

The classifications of impact spatter based on the size of droplets and from the velocity of an applied force are [BLANK], [BLANK], and [BLANK] impact spatter.

False

True or False: The velocity of an applied force is a good way to classify impact patterns and to determine the kind of force that produced them.

area of convergence

The [BLANK] is the point on a 2-D plane from which the drops originated.

area of origin

The [BLANK] of a bloodstain pattern in 3-D space illustrates the position of the victim or suspect when the stain-producing event took place.

string

The [BLANK] method is used at the crime scene to determine the area of origin.

transfer pattern

A(n) is created by contact between a bloody object and a surface.

lightens

The pattern made by a bloody object dragged across a surface (lightens, darkens) as the object moves away from the point of contact.

True

True or False: Footwear transfer patterns created by an individual who was running typically show imprints with more space between them than those of an individual who was walking.

True

True or False: The direction of a flow pattern may show movements of objects or bodies while the flow was still in progress or after the blood had dried.

pool

The approximate drying time of a(n) [BLANK] of blood determined by experimentation is related to the environmental conditions of the scene and may suggest how much time has elapsed since its deposition.

skeletonize

The edges of a bloodstain will generally [BLANK] within 50 seconds of deposition and be left intact even if the central area of a bloodstain is altered by a wiping motion.

castoff

A(n) [BLANK] pattern commonly originates from repeated strikes from weapons or fists and is characterized by an arc pattern of separate drops showing directionality.

False

True or False: Characteristics of a cast-off pattern arc cannot give clues about the kind of object that was used to produce the pattern.

arterial spray spatter

When an injury to an artery is suffered, the pressure of the continuing pumping of blood projects blood out of the inured area in spurts, creating a pattern known as [BLANK].

trail

If a(n) [BLANK] pattern is found at a scene, it may show movement, lead to a discarded weapon, or provide identification of the suspect by the suspect’s own blood.

expirated blood

A bloodstain pattern created by [BLANK] features bubbles of oxygen in the drying drops an may be lighter in color than the impact spatter.

void

The shape and size of the blank space, or [BLANK], created when an object blocks the deposition of spatter onto a surface and is then removed, may give a clue about the size and shape of the missing object or person.

True

True or False: Each bloodstain pattern found at a crime scene should be noted, studied, and photographed.

grid method

When documenting bloodstain patterns, the [BLANK] involves setting up a grid of squares of known dimensions over the entire pattern and taking overview, medium-range, and close-up photographs with and without the grid.

perimeter ruler method

The [BLANK] method of bloodstain documentation involves setting up a border of rulers around the pattern and then placing a small ruler next to each stain to show relative position and size in photographs.

True

True or False: The pointed end of a bloodstain always faces towards its direction of travel.