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Amanda Knox and DNA Contamination

Posted by Osagie K. Obasogie on February 27th, 2014


The trial of former American exchange student Amanda Knox captivated much of America a few years ago – at least those who are fans of Nancy Grace. Her conviction for murdering housemate Meredith Kercher in Italy and subsequent acquittal were daily fodder for many newsfeeds. Thus, it should be no surprise that her retrial and recent conviction for the very same murder has rekindled the obsession that many have with this case.

Central to the inquiry is what, if any evidence, links Knox to the Kercher murder. Knox’s retrial led to new DNA tests on a knife that prosecutors said could be the murder weapon. But Greg Hampikian – founder and director of the Idaho Innocence Project – voiced serious concerns about this evidence. From the BBC:

some independent forensic scientists told the BBC this knife (which had been considered a possible murder weapon) should never have been given the importance it was because there was no evidence of blood found on it. . . .  "I could see the problem with the case right away," says Dr Hampikian. . . .
A knife recovered from Sollecito's house was found to have Ms Knox's DNA on the handle and a small amount of DNA on the blade "consistent with the victim". . . . [Hampikian said] "That is significant because Miss Kercher had never gone to that house, so what is she doing on the blade of the knife? "While that may seem on its face to be evidence of a crime, in order to substantiate such a small amount of DNA you look for blood, and I can't emphasise enough how small this was - it was just a few cells." But there was no evidence of blood or any other body fluids found, the Boise State researcher points out. "You can't really wash the blood off and leave the DNA in any practical sense. That means that the few cells or molecules might have been from the laboratory after they amplified Miss Kercher's DNA," he explains. . . .
This concern was not his alone. There have been claims that the initial evidence was handled using dirty gloves and that investigators entered the crime scene without protective clothing. . . . To highlight how easily contamination in DNA evidence can occur, Dr Hampikian's team carried out a demonstration. They picked up used drink cans wearing clean gloves and then placed a new knife into an evidence bag without changing gloves. The knife was subsequently found to have tiny fragments of traceable DNA which had been transferred from the can.

The contamination of crime scene evidence has been known to falsely implicate suspects. While countless hours have been spent on this case, perhaps this is one area where the Italian courts should spend a little more time. 

Previously on Biopolitical Times:





Posted in Biotech & Pharma, DNA Forensics, Osagie Obasogie's Blog Posts, Other Countries


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