Bloodstain pattern analysis is a section of forensic studies, that deals with the analysis of spots and splashes of blood. Any achievement in science, especially in the analysis of blood and DNA molecules are widely used by detectives and criminologists for investigations and catching criminals. Therefore, despite the fact that the forensic examination of blood stains is not new to criminology, new technologies are allowing to achieve much better results using this technique and making it more common. Analysis of samples of blood stains requires extensive practical knowledge of such sciences as chemistry, biology, physics and geometry.(Culliford 12)
There are two classification systems of blood traces: elementary traces - individual tracks, giving information about the physical factors that shaped them, depending on the surface properties, and complex traces - a set of tracks, which gives information about the dynamics of their formation. Each of these systems is divided on the types that concretize the information obtained during examination of blood traces.
Bloodstain pattern analysis are usually made by studying following types of blood traces at the crime scene: puddles of blood, traces left in the process of moving the body, impregnation, drips, drops of blood, splashes, blots, inertial traces.
Bloodstain analysis is very crucial for crime investigations. They can give answers to the most important questions: what have occurred and what have not occurred?; where did the event take place?; approximately when and in what sequence?; where the victim and the aggressor were in relation to each other?; where did the events take place? (Ackermann 33)
Scientists use basic principles of behavior of blood using deep knowledge in biology, cohesion, capillary action and velocity according to the physics. They also pay attention to geometry, angle and velocity summing up knowledge in mathematics. All of the following helps investigators to find out: where did the blood come from, how the wounds were caused, the direction of the hit that caused the wound, position of the victim and the perpetrator at the moment of conflict, is there only one perpetrator or many potential perpetrators.
Form of splashes depends on the angle of incidence of the flying droplets barrier. If it is close to 90 degrees, the form should be rounded. With decreasing of angle sprays acquire roundness, becoming similar in configuration to the exclamation mark. With significant flight speed spray, round and oval spots become jagged or radial edge. Sharp end of next spray is always directed towards the flight and is often interrupted. Sometimes the fan-shaped spray located about the center of dispersal of the drops of blood.(Wonder 45)
The problem appears when the object on which the blood falls, can absorb well, the original form in the following level can be further significantly changed. Traces formed on objects that do not have the ability to absorb the blood, usually retain their original appearance.
The study of blood stains in the form of spray is important, as it helps to establish forensic circumstances of their occurrence. When life blood splatter formed in injuries mainly arteries repeated blunt trauma (especially on the head), hand-waving bleeding during combat, defense, movement of the victim. Spots of blood splashes are usually located in a limited area in the form of a straight band, fans, arc cone. They are characterized by uniformity of size and shape. Most often, they are small, round and oval, some are shaped like an exclamation mark, densely arranged. The narrow end of the oval is directed in the direction of motion of the droplet.
Works Cited
Culliford, Bryan J. The Examination And Typing Of Bloodstains In The Crime Laboratory. Washington: National Institute of Law Enforcement and Criminal
Justice; for sale by the Supt. of Docs., U.S. Govt. Print. Off., 1971. Print.
Wonder, Anita Y. Bloodstain Pattern Evidence: Objective Approaches And Case Applications. Burlington, MA: Elsview Academic Press, 2007. Print.
Ackermann, Rolf, Heiko Artkämper, and Horst Clages. Kriminalistik Gestern - Heute - Morgen. Stuttgart: Boorberg, 2013. Print.
