Scientific approaches in bloodstain analysis (crime scene investigation)
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Authors
Trumbo, William Y.K.
Issue Date
2011
Type
Thesis
Language
en
Keywords
Forensic Sciences
Alternative Title
Abstract
Forensic science or forensics is the scientific processing of information found at the crime scene. The facts derived from the analysis can be used as evidence in the justice system. Blood is one of the most common types of physical evidence found at a crime scene. Understanding how blood interacts with various surfaces is most important during analysis. This understanding and knowledge can lead to discovering details that are essential too reconstructing events at the crime scene. The process of deducting what events led to a given bloodstain pattern requires exigent and complex analysis. This thesis project seeks not to expound exigently. It presents calculationbased methods that automate point-of-origin and area-of-origin of the bloodstain. Blood leaving the body is subjected to atmospheric conditions: for example specific gravity and force. Surface tension will cause the blood drop to be pulled horizontally and vertically. Because blood droplets are influenced by drag force, the drops will settle into a spherical shape as a result of the surface tension. Determining the angle of impact requires measuring the stains length and width. The angle of impact can be defined as the acute angle which is formed between the area of the blood droplet and the target surface location. Point-of-convergence is the intersection of two bloodstain paths and is important in determining bloodstain directional travel. A stain on a surface can be traced based on the stains long axis. Understanding the bloodstain patterns allows the forensic analyst to interpret and provide the following information: type of weapon used in the crime and movement of victim and assailant after the bloodshed began.