Bloodstain pattern analysis: investigating the effectiveness of small (sub 3mm) bloodstains in area of origin determinations

The use of bloodstain pattern analysis (BPA) in reconstruction of bloodletting events has become a critical and integral part of many criminal investigations and court cases. In instances where a bloodstain pattern is created due to external forces being applied to a source of blood, an impact spatter pattern is created. Traditionally, BPA analysts have followed a rigid protocol for selection of bloodstains used in these reconstruction events in attempts to lessen sources of error that directly impact area of convergence (AOC) and area of origin (AOO) calculations. One such selection criteria is bloodstain size; bloodstains that have a length (l) between 3mm and 8mm are considered useful for reconstruction determinations. The purpose of this study was to evaluate the effectiveness of small (l