Blood Stain Evidence in Criminal Cases

This paper will discuss various aspects of blood stain evidence, particularly with regard to the O.J. Simpson case. The first part of the paper will discuss the interpretation of blood spatter evidence in general. The second part of the paper will look at the Simpson case with regard to such interpretation.

The analysis of blood stain and blood spatter evidence is quite distinct from that of the blood itself. While blood analysis looks at the chemical and DNA characteristics of blood samples taken as evidence, blood stain and blood spatter analysis examines the patterns of the blood found at the crime scene. Blood sample testing is used to identify the persons at the crime scene; blood stain/spatter evidence is used to explain the sequence of events which took place and the manner in which the criminal act was committed.

Analysis of blood spatter has essentially evolved since the 1930s, when French researchers began systematically classifying blood stains based upon their shapes and began studying blood drops through the use of high-speed photography. In 1971, Professor Herbert MacDonell published the seminal work in this area, Flight Characteristics and Stain Patterns of Human Blood. This work has since become the basis of all blood spatter analysis and is still the most complete work on the subject. Ironically, Dr. MacDonell was an expert witness for the defense in the Simpson trial.

. . .
ch falls will produce spattering in the form of long narrow streaks with few small round spots. Impacts of 5 to 25 feet per second result in medium velocity blood spatters. Such impacts include those from blunt instruments, such as clubs, hammers, and bricks. The blood is broken up into many small droplets measuring less than 1/8 inch in diameter. Although these stains are easily distinguishable from the large spots which are produced by normal drops, they can be hard to distinguish from the "cast off" spots produced by the motion of a bloody object. Analysts must be experienced in order to differentiate between the two types of spatters. Impacts greater than 25 feet per second produce high velocity spatters. These spatters are characterized by a high percentage of very fine blood specks. The spatters usually exhibit a "mist" dispersion which is similar to an aerosol spray. Particles of such low mass will rarely travel more than 3-4 feet horizontally. Larger droplets of less than 1/8 inch will also be produced by such an impact. These larger droplets will travel several feet from the impact site. High velocity blood spatter is usually produced by gunshot wounds. "Cast off" spatter is produced by the motion of a
. . .

Some common words found in the essay are:
Dr MacDonell, Herbert McDonell, OJ Simpson, Ron Goldman, blood spatter, Human Blood, Times July, Nicole Brown's, Army Lawyer, blood drop, Herbert MacDonell, Forensic Sciences, blood spatter analysis, spatter evidence, spatter analysis, target surface, sock wearer, blood stain, blood spot, puddle blood, crime scene, blood spatter evidence, crime scene blood, motion bloody object, blood cast object,
Approximate Word count = 1835
Approximate Pages = 7 (250 words per page)

More Essays on Blood Stain Evidence in Criminal Cases