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A Blind Trial Evaluation of a Crime Scene Methodology for Deducing Impact Velocity and Droplet Size from Circular Bloodstains *
Author(s) -
HulseSmith Lee,
Illes Mike
Publication year - 2007
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2006.00298.x
Subject(s) - range (aeronautics) , volume (thermodynamics) , statistics , confidence interval , violent crime , mathematics , materials science , analytical chemistry (journal) , physics , chromatography , chemistry , composite material , criminology , sociology , quantum mechanics
In a previous study, mechanical engineering models were utilized to deduce impact velocity and droplet volume of circular bloodstains by measuring stain diameter and counting spines radiating from their outer edge. A blind trial study was subsequently undertaken to evaluate the accuracy of this technique, using an applied, crime scene methodology. Calculations from bloodstains produced on paper, drywall, and wood were used to derive surface‐specific equations to predict 39 unknown mock crime scene bloodstains created over a range of impact velocities (2.2–5.7 m/sec) and droplet volumes (12–45 μL). Strong correlations were found between expected and observed results, with correlation coefficients ranging between 0.83 and 0.99. The 95% confidence limit associated with predictions of impact velocity and droplet volume was calculated for paper (0.28 m/sec, 1.7 μL), drywall (0.37 m/sec, 1.7 μL), and wood (0.65 m/sec, 5.2 μL).