The victim was found partially submerged. She had been in the water for 8-10 hours. There were signs of sexual assault, but serological testing revealed no sign of semen and/or spermatozoa on the victim's panties.
The M-Vac was used to sample the crotch area and the waist bands. The resulting samples were concentrated utilizing the centrifuge method. Only the crotch sample had a positive quantification for male DNA. The ratio of male to female DNA was 6000:1. It was amplified using Applied Biosystems YFiler YSTR amplification kit.
Despite the extreme ratio, a partial Yfiler profile (9 of 17 loci) from a single male contributor was obtained.
In Sorenson Forensic's opinion, processing with the M-Vac allowed the minimal amounts of male DNA to be collected despite overwhelming female/victim DNA, exposure to the effects of water and a limited amount of cellular material or touch DNA.
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