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CBS "48 Hours": Exculpatory DNA may have sent an innocent man to prison

New York, NY

CBS presented the 1979 Janet Walsh cold case homicide on "48 Hours" on May 16. Gregory Scott Hopkins, who had a previous sexual relationship with Walsh, was convicted in 2013. The program said the prosecutor's outside forensic pathologist claimed to know exactly how and when the DNA was deposited. Cybergenetics' Dr. Mark Perlin explained the proximity "coincidence" as possible transfer between wet cotton fabrics, subjected to pressure for a long time. But the celebrity pathologist testified he couldn’t "envision" DNA transfer.

As "48 Hours" reported, the prosecutor said, "We always go back to location, location, location. Because the location of the DNA is what tells us when it was put there." But DNA expert Perlin noted, "In this case, the prosecution said there was only one possibility, and that's clearly false. And in science, if you have two possibilities that can equally explain the data, it's a wash." Nor could the prosecutor explain Hopkins' invisible semen, evidence that these old DNA stains were deposited long before the murder.

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