Investigation of factors affecting the region of origin estimate in bloodstain pattern analysis

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Medical Physics
Degree name
Master of Science
Publisher
University of Canterbury. Physics and Astronomy
Journal Title
Journal ISSN
Volume Title
Language
Date
2006
Authors
Wells, Joanna Kathleen
Abstract

The causes of errors in the angle of impact calculation were investigated including the surface type, falling velocity and the method used to fit an ellipse to a bloodstain. As had been cited previously the angle of impact was generally underestimated, especially at acute angles and the reason for this was determined to be due to an overestimation of the length of a bloodstain. The surface type was found to significantly affect the accuracy of an angle of impact calculation and as the falling velocity increased, the angle of impact calculation became more accurate. High-speed photography was used to further investigate the formation of bloodstains on surfaces. It was found that the formation of the bloodstain varied depending on the surface type and the angle of the surface. Bloodstain pattern analysis involves the application of scientific techniques to reconstruct events that resulted in a bloodstain pattern. The position of the blood source in three-dimensional space is a fundamental element of this application. Currently little is known about the methods used by bloodstain pattern analysts to select bloodstains when determining the region of origin. Fourteen analysts worldwide were surveyed in order to ascertain this information. It was found that the methods used were variable and were often not based on scientific research. Research was therefore undertaken into bloodstain selection and in particular, which bloodstains should be selected for a region of origin analysis. As a result of these experiments, two sets of selection criteria were established, one for use when the region of origin is being calculated manually and one for when directional analysis is being used.

Description
Citation
Keywords
Forensic Science, Bloodstain Pattern Analysis, BPA, Crime Scene Reconstruction, Crime Scene Investigation, Blood, Region of Origin, Angle of Impact, Impact Spatter, Blood Spatter
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
Copyright Joanna Kathleen Wells