A cast-off pattern is created when a object flings blood in an arc onto a • nearby surface. This kind of pattern commonly occurs when a person pulls a bloody fist or weapon back between delivering blows to a victim. The characteristic arterial spray spatter is created when a victim suffers an injury to a • main artery or the heart and the pressure of the continuing pumping of blood projects blood out of the injured area in spurts that are apparent in the pattern. Expirated blood is expelled from the mouth or nose and may appear as very fine • spatter or large low-velocity bloodstain clusters. This kind of pattern may contain bubbles of oxygen or be mixed with saliva. A void pattern features an area free of spatter where an object (or person) blocks the • deposition of blood spatter onto a target surface or object. Because the spatter is deposited onto the object or person instead, the shape of the void may give a clue as to the size and shape of the missing object or person. Transfer patterns are created when an object with blood on it makes simple contact with a • surface or moves along a surface. The direction of movement may be shown by feathering of the pattern. Flows may originate from a single drop or a large amount of blood. The direction of the • flow is caused by gravity, so the direction of a pattern may suggest the original position of the surface when the flow was formed. A pool is formed where large amounts of blood collect. The pool may be absorbed into • the surface of deposition over time. The presence of skeletonization of the perimeter of a bloodstain suggests that the stain • was disturbed after the edges have sufficient time to skeletonize. A trail pattern is separate from other patterns, and it is formed by single blood droplets • dripping off an object or injury. Photographs and sketches should first be created of the overall pattern to show orientation • of the pattern to the scene. Medium-range and close-up photographs may use the grid method or perimeter ruler • method to show the orientation and relative size of the pattern and individual stains. Questions 1. What is crime scene reconstruction? 2. Which of the following is of paramount importance in the interpretation of bloodstain patterns? a. The direction of impact b. The surface texture c. The angle of impact
• A cast-off pattern is created when a object flings blood in an arc onto a nearby surface. This kind of pattern commonly occurs when a person pulls a bloody fist or weapon back between delivering blows to a victim. • The characteristic arterial spray spatter is created when a victim suffers an injury to a main artery or the heart and the pressure of the continuing pumping of blood projects blood out of the injured area in spurts that are apparent in the pattern. • Expirated blood is expelled from the mouth or nose and may appear as very fine spatter or large low-velocity bloodstain clusters. This kind of pattern may contain bubbles of oxygen or be mixed with saliva. • A void pattern features an area free of spatter where an object (or person) blocks the deposition of blood spatter onto a target surface or object. Because the spatter is deposited onto the object or person instead, the shape of the void may give a clue as to the size and shape of the missing object or person. • Transfer patterns are created when an object with blood on it makes simple contact with a surface or moves along a surface. The direction of movement may be shown by feathering of the pattern. • Flows may originate from a single drop or a large amount of blood. The direction of the flow is caused by gravity, so the direction of a pattern may suggest the original position of the surface when the flow was formed. • A pool is formed where large amounts of blood collect. The pool may be absorbed into the surface of deposition over time. • The presence of skeletonization of the perimeter of a bloodstain suggests that the stain was disturbed after the edges have sufficient time to skeletonize. • A trail pattern is separate from other patterns, and it is formed by single blood droplets dripping off an object or injury. • Photographs and sketches should first be created of the overall pattern to show orientation of the pattern to the scene. • Medium-range and close-up photographs may use the grid method or perimeter ruler method to show the orientation and relative size of the pattern and individual stains. Questions 1. What is crime scene reconstruction? 2. Which of the following is of paramount importance in the interpretation of bloodstain patterns? a. The direction of impact b. The surface texture c. The angle of impact
Blood%20Spatter%20Study%20Guide%205.08.15.docx