Crime Scene Reconstruction: Bloodstain Pattern Analysis Lesson 2: General Features of Bloodstain Formation March 9, 2015 Sanders

Bloodstain Formation Individual bloodstains can convey to the bloodstain analyst the directionality of impact of the blood when it impacted a surface. Bloodstain Analysis

Bloodstain Patterns Bloodstain patterns may convey to the analyst The location of victims or suspects The movement of bleeding individuals Number of blows delivered Minimum number of blows that struck a bleeding victim Bloodstain Analysis

Information from Pattern Interpretation The direction from which blood originated. The angle at which a blood droplet struck a surface. The location or position of a victim at the time a bloody wound was inflicted. The approximate location of an individual delivering blows that produced a bloodstain pattern. Bloodstain Analysis

Bloodstain Pattern on the Wall Bloodstain Analysis

Surface Texture Surface texture is of utmost importance in the interpretation of bloodstain patterns. When reconstructing the scene, an analyst must use identical surfaces. Bloodstain Analysis

Smooth Surfaces Smooth, nonporous surfaces produce rounder droplets. Glass Linoleum Metal Marble Other polished stone surfaces Bloodstain Analysis

Rough Surfaces Rough or porous surfaces create irregularly shaped bloodstains. Wood Plaster Bloodstain Analysis

Satellite Spatter Small drops of blood that are distributed around the perimeter of a drop of blood and were produced by blood hitting a surface. Bloodstain Analysis

Direction of Travel The direction of travel of blood striking an object may be determined by the stain’s shape. The pointed end of the of a bloodstain always faces away from the direction of travel. Bloodstain Analysis

Angle of Impact The angle of impact is the angle formed between the path of the blood drop and the surface that it contacts. Bloodstain Analysis

Angle of Impact The angle of impact of an individual bloodstain can be approximated by the degree of distortion or lengthening of the bloodstain. Bloodstain Analysis