Researchers Find Fiber Evidence Lasts Longer Underwater Than Previously Thought
by Jo Ellen Nott
People have long looked to bodies of water as safe places to dispose of and forever hide evidence of their crimes. They believed that by tossing murder weapons or victims into the depths of rivers, lakes, and oceans, they could escape punishment. However, advancements in forensic science and dive technology are allowing the recovery of more evidence.
A groundbreaking study from Staffordshire University in England disproves the longstanding belief among crime scene experts that just after a week underwater, fiber evidence on fabrics is lost. For years, law enforcement agencies would not collect fiber evidence after that time frame.
The study, published in Forensic Science International and conducted by British, German, and Italian researchers, debunks that belief. The researchers found that even after four weeks, a third of the fibers from the least resilient fabrics remained. This means that valuable evidence could be lost if investigators prematurely abandoned underwater searches.
The researchers used mesocosms, or controlled artificial streams, and submerged three common fabric types for four weeks in both high and low flow water conditions. The use of mesocosms have long been used for ecological research, but this study of fiber resistance in aquatic environments was the first time they have been leveraged for forensic research, according to Forensic.
The researchers tested three textiles: (1) woolen/nylon mix carpet, (2) 100 percent polyester fleece, and (3) 95 percent polyester/5 percent elastane sports vest at two water flow rates over a four-week period. They made their groundbreaking discovery after observing that while a significant amount of shedding occurred—up to 81 percent—in the first 24 hours, the shedding then slowed dramatically and allowed a third of the fibers to remain.
“This clearly indicates that it is extremely valuable to search for fiber evidence even after a long exposure time,” study author Claire Gwinnett observed.
The study also revealed that fabric type plays a key role in fiber persistence. Rougher textures, like woolen carpets, shed less readily than smoother ones, like sports vests. This finding highlights the importance of considering not just time submerged but also fabric characteristics when assessing evidence potential.
In addition to the immediate implications for the retrieval and examination of fiber evidence, the European scientists see a broader potential use of mesocosms to study the persistence of gunshot residue, pollen, fingerprints, and even DNA aquatic in environments.
Sources: Forensic, Divers Alert Network
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