New research from North Carolina State University offers insights into how blood stains cotton fabrics, aiding forensic investigations. The study focuses on understanding the velocity of blood when it strikes different fabric surfaces, which can help investigators draw conclusions about crime scenes.
“When blood strikes fabric, it leaves a stain,” said Tiegang Fang, the corresponding author of the study and a professor at NC State. He explained that determining the speed at which blood travels upon impact is challenging due to how blood spreads across fabric fibers.
The research evaluated five fabric surfaces using porcine blood applied at 12 velocities. High-speed cameras captured the impact and spread of blood on these fabrics. Analysis revealed patterns correlating with blood spatter velocity.
“One key finding relates to the ‘fingers’ of the blood stain,” Fang noted. These tendrils indicate faster-moving blood, but they may merge over time. Satellite droplets also served as velocity indicators; more droplets suggest higher speeds.
Plain-woven cotton was found to be easier for estimating spatter velocity compared to twill, which posed challenges due to its properties.
“The results of this study are promising,” Fang stated, expressing interest in exploring more fabric types and weaves.
The paper titled “Dynamics of blood falling on three types of cotton fabrics and resulting bloodstains” is published in Forensic Science International. Fujun Wang, Vanessa Gallardo, and Stephen Michielsen co-authored it with support from the National Institute of Justice under grant 2018-R2-CX-0033.
