CHAPTER 4 Review Questions - CRIME SCENE RECONSTRUCTION: BLOODSTAIN PATTERN ANALYSIS

___ is the method used to support a likely sequence of events at a crime scene by the observation and evaluation of physical evidence and statements made by individuals involved with the incident.

Crime-scene reconstruction

Reconstructing the circumstances of a crime scene is a team effort that may include the help of law enforcement personnel, medical examiners, and ___.

Criminalist

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

Blood stain patterns

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

Control Experiment

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

Victim/ Assailant

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

True

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

Increases

The ___ and ____ of blood striking an object may be discerned by the stain's shape.

_____

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

Circular

The angle of impact of an individual bloodstain cab be estimated using the ratio of ___ divided by ____.

Width of blood divided by length of blood stain

___ 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.

Impact spotter

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

False

The classification system of impact spatter is based on the size of drops resulting from the velocity of the blood drops produced, and patterns can be classified as ___, ____, or ____ impact spatter.

low, medium, high-velocity

The velocity classification system is a good way to classify impact patterns and to determine the kind of force that produced them.

False

The ___ is the point on a two-dimensional plane from which the drops originated.

Area of convergence

The ___ of a bloodstain pattern in s three-dimensional space illustrates the position of the victim or suspect when the stain-producing event took place.

Area of origin

The __ method is used at the crime scene to determine the area of origin.

String

A ___ is created by contact between a bloody object and a surface.

Transfer Pattern

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

Lightens

Footwear transfer patterns created by an individual who was running typically show imprints with more space between them compared to those of an individual who was walking.

True

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.

True

The approximate drying time of a ___ of blood determined by experimentation is related to the environmental condition of the scene and may suggest how much time has elapsed since its deposition.

Skeletonization

The edges of a bloodstain generally ____ within 50 seconds of deposition and are left intact even if the central area of a bloodstain is altered by a wiping motion.

Dry

A ____ pattern commonly originates from repeated strikes from weapons or fists and is characterized by an arc pattern of separate drops showing directionality.

Cast-off

Characteristics of a cast-off pattern arc cannot give clues as to the kind of object that was used to produce the pattern.

False

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

Arterial spray

If a ___ pattern is found at a scene, it may show movement, lead to a discarded weapon, or provide identification of the suspect by his or her own blood.

Drip trail

A bloodstain pattern created by ___ features bubbles of oxygen in the drying drops and may be lighter of oxygen in the drying drops and may be lighter in color when compared to impact spatter.

Expirated blood pattern

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

Void

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

True

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

Grid Method

The ___ 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.

Perimeter Ruler

The pointed end of a bloodstain always faces toward the direction of travel.

True