Preliminary Study, Analyzing the Halo Effect: Factors Involved in Sequencing the Deposition of Overlapping Bloodstains Caused by Wipe Patterns and Blood Droplets

Christen Corby, Caitlyn Hauke, Brian Gestring, Lawrence Quarino

Abstract


Sequencing the order of overlapping bloodstains is an area of crime scene reconstruction that is often overlooked in current evaluation methods.  This study examined the patterns observed when blood wipes and droplet bloodstains overlap and how variables such as blood volume and substrate affect such patterns.  This research revealed that a red halo of blood often formed around droplets when wipe patterns were produced over blood droplets.  This feature was consistently found when droplets were made on several nonabsorbent, smooth substrates with volumes of blood ranging from 5-100µL.  Additionally, a substrate-colored halo was often produced around the droplets when droplets were placed on top of blood wipes on several smooth, nonabsorbent substrates.  This feature was often found when the volume of the blood swipe was larger (50 or 100µL) and the droplet volume ranged from 10-100µL.  The presence of “halos” around blood droplets in overlapping bloodstains may therefore be helpful in determining the order of bloodstain deposition.


Keywords


Overlapping bloodstains; Bloodstain sequencing; Bloodstain pattern analysis; Wipe patterns; Blood droplets

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ISSN 1942-7794