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Justice denied: Mr. Hopkins invisible semen
M.W. Perlin, "Justice denied: Mr. Hopkins invisible semen", American Investigative Society of Cold Cases Annual Conference, St. Louis, MO, 28-Jun-2016.
PowerPoint presentation with live audio recording of Dr. Perlin's talk.
Cold case DNA can catch the wrong man. In 1979, Janet Walsh (23) was killed in her Monaca, Pennsylvania home. Thirty years later, DNA on her nightshirt, and adjacent bathrobe tie binding her hands, was linked to lover Scott Hopkins.
Two items in one location: "DNA left at the same time," said the prosecution. But consensual DNA on a wet nightshirt can transfer weeks later when pressed for minutes against cotton fabric. Two items in one location: "DNA left at different times," said the defense.
Hopkins semen stains were invisible, undetected in 1979 by the investigator, pathologist, coroner and criminalist. New crime stains would have been seen. Hopkins serves an eight year sentence, convicted by bad science.
- CBS "48 Hours": Janet's Secret - CBS News