Bloodstain pattern analysis (BPA) is one of many specialties in the field of forensic science; the science of bloodstain pattern analysis use scientific knowledge from other fields to solve problems. BPA also uses the scientific method to examine bloodstain evidence at a crime scene where blood is present by gathering information, observing, documenting, analyzing, evaluating, and technical or peer reviewing. A bloodstain pattern analysis job is to collect, categorize and interpret the shape and distribution of bloodstains within a crime scene (Peschel, 2011). Bloodstain patterns can reconstruct a crime scene and then determine the crime as an accident, homicide, or suicide; the blood can also identify the location, quality and intensity of an external force. The purpose of a BPA’s is to determine bloodstain patterns and to recreate the action that caused the blood.
The Locard’s principle is important in any forensic science field, “the principle holds that the perpetrator will take away traces of the victim and the crime scene; the victim will retain traces of the perpetrator and may leave traces of himself or herself on the perpetrator; and the perpetrator will leave traces of himself or herself at the crime scene in many ways” (Geberth, 2007). The Locard’s principle in BPA is applied in the retrieval and evaluation of bloodstain pattern evidence.
Classification of Bloodstain Patterns
In order to reconstruct a crime scene, analysis must classify the bloodstain spatter, and there are many way to classify blood stain patterns: bloodstain spatter by velocity and bloodstain through taxonomy. In the classification of the bloodstain spatter by velocity, there are three basic categories of stain groups based on the concept that the size of the bloodstain compared with the amount of force propelling that bloodstain, and they are Low-Velocity Impact Spatter (LVIS), Medium-Velocity Impact Spatter (MVIS) and High-Velocity Impact Spatter (HVIS). Low-velocity is considered to be a force of energy equivalent to normal gravitational pull up to a force or energy of five feet per second (5ft/s); this stain is relatively large, usually 4 mm in diameter or greater (Geberth, 2007). Medium-velocity is considered when a source of blood is subjected to a force of from five to twenty-five feet per second; the stains are ranged from 1 to 4 mm in diameter and they are associated with beatings or stabbings (Geberth, 2007). High-velocity bloodstains are created when the source of the blood is subjected to a force with a velocity greater that 100 feet per second (100 ft/s); the stain is most likely less than 1 mm in diameter although smaller and larger stains may be observed, and these types stains are usually associated with gunshot injuries (Geberth, 2007). The classification of bloodstain through taxonomy is when bloodstains and patterns are classified based on their physical feature of size, shape, location, concentration and...