ABSTRACT
This chapter considers one discipline: bloodstain pattern analysis (BPA). Complete analysis of bloodstain patterns requires specific training and experience. When presented with situations involving such evidence, specialists will typically be brought in to assist. As with all evidence the basic responsibility of a crime scene investigator is to collect the evidence in a fashion sufficient that subsequent analysis can be accomplished. There are three underlying principles that guide the behavior of the bloodstain pattern analyst. They are the pattern diversity principle, the principle of stain shape and vector correlation, and the physically altered bloodstain (PAB) Principle. Pattern diversity is the core concept behind BPA and was recognized more than one-hundred and fifty years ago. The principle of stain shape and vector correlation is a significant consideration in the examination of a variety of stains found in crime scenes. PAB principle can be articulated as: Once exposed blood will react to environmental conditions in a predictable manner.
