ABSTRACT
The geometric analysis of human bloodstain patterns at crime scenes is not a new idea, but it has acquired much greater recognition over the past several decades. Bloodstain pattern analysis should be viewed as a forensic tool that assists the
investigator or the forensic scientist to better understand what took place and what could not have taken place during a bloodshed event. In this sense, is it is a form of crime scene reconstruction and can be used as we discussed in the last chapter. The information obtained from the analysis of bloodstain patterns may assist in apprehending a suspect, corroborate a witness’s statement, assist in interrogating suspects, and allow for the reconstruction of past events. As with any tool, bloodstain pattern analysis has its strengths and weaknesses. The analysis will only be as valid as the information available and the ability of the examiner performing the analysis. (For a discussion of career preparation for blood stain analysis, see Sidebar 4.1.)
The analysis of bloodstains and patterns has been documented in books, journals, and articles for centuries (see Sidebar 4.2), but the science of bloodstain pattern analysis in modern form emerged in the 1800s. Original research and experimentation with bloodstains and patterns was done by the French scientist Dr. Victor Balthazard, whom we met in Chapter 1, and his associates, who presented the material as a paper at the 22nd Congress of Forensic Medicine in 1939. The use of bloodstain pattern analysis as a recognized forensic discipline in the modern era dates back to 1955, when Dr. Paul Kirk of the University of California at Berkeley submitted an affidavit of his examination of bloodstain evidence and findings in the case of State of Ohio v. Samuel Sheppard. This was a significant milestone in the recognition of bloodstain evidence by the American legal system. In 2002, the Scientific Working Group on
SIDEBAR 4.1. CAREER PREPARATION AND EXPECTATIONS
Bloodstain analysts represent a range of forensic scientists and crime scene investigators with diverse levels of education. The courts have accepted testimony from individuals with strong backgrounds in chemistry, biology, and physics, many of whom possess degrees in science or forensic medicine. Many of these individuals are employed in crime laboratories or medical examiner offices that have crime scene responsibilities. Crime scene investigators, evidence technicians, and detectives who do not necessarily possess scientific backgrounds have also offered expert testimony. There are also training courses available for bloodstain pattern analysis both at the university and professional levels.
