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Defining a Methodology for Bloodstain Pattern Analysis

NCJ Number
Journal of Forensic Identification Volume: 56 Issue: 4 Dated: July/August 2006 Pages: 549-557
Ross M. Gardner
Date Published
July 2006
9 pages
Building on Saviano's publication entitled, "Articulating a Concise Scientific Methodology for Bloodstain Pattern Analysis," this article provides an expanded, detailed explanation of the application of the scientific method to bloodstain pattern analysis, suggesting additional steps and questions to be posed in this process.
Saviano proposes an eight-step process for bloodstain pattern analysis: data collection, case review, isolation/description of patterns, formulation of a hypothesis, testing of the hypothesis, formulation of theories, testing of theories, and conclusions and results. This process fails to address one important area, i.e., the isolation and analysis of the individual patterns, which is the key to all subsequent effort. Individual pattern recognition and analysis is the core of bloodstain pattern analysis; this requires that each individual pattern be subjected to the scientific method of analysis. At its core, the scientific method involves defining objective questions, seeking and finding answers to those questions, and then applying the answers to those questions in solving larger more complex questions. Thus, posing and answering questions is the heart of the scientific method. The ultimate question in bloodstain pattern analysis is, "How was this stain created?" To determine the answer, the analyst must ask and answer a number of questions. Before the scientific method can be useful, the analyst must ask the right questions and in the right order. This article proposes a seven-step process for doing this: become familiar with the entire scene; identify individual patterns among the many bloodstained surfaces; categorize these patterns based on an established taxonomy; evaluate aspects of direction and motion for the pattern; evaluate angles of impact, points of convergence, and areas of origin; evaluate interrelationships among patterns and other evidence; and evaluate viable source events to explain the patterns based on the previous steps. 4 references