Amanda Knox Defense Expert Pushes DNA Errors in Murder Trial

Expert in Amanda Knox murder trial said DNA samples may have been contaminated.

ByABC News
September 26, 2009, 12:18 PM

PERUGIA, Italy, Sept. 26, 2009— -- A DNA expert found fault with the prosecutor's evidence in the Amanda Knox trial in what has become an ongoing theme for the defense trying to free the 22-year-old American exchange student on trial for murdering her British roommate.

In testifying for Knox, expert Sarah Gino, who has appeared in court before, called out the prosecution for providing amplified DNA samples with the dates missing.

These dates are important, Gino said, "because they would tell us what samples were tested together on the same day, which might indicate if some of them could have been contaminated."

She also said dating the procedure for each sample was important to ensure that the amplification did not happen twice by mistake. She called the amplification of DNA the "key moment" in DNA analysis.

Gino was one of the last two witnesses during the seven-month trial, which has seen more than 100 witnesses for 42 hearings in what has become known in Italy as the "trial of the century." The case will now move onto the next phase of the trial.

Knox, an exchange student from Seattle is accused, along with her former Italian boyfriend Raffaele Sollecito, 25, of sexually assaulting and killing Meredith Kercher, 21, with whom Knox shared a cottage on the outskirts of this picturesque hill town.

Kercher was found dead in her room Nov. 2, 2007, semi-naked with her throat cut.

A third person, Rudy Guede, 22, who was accused of the crime along with Knox and Sollecito, opted for a fast-track trial and was convicted in October 2008 to 30 years in prison for his role in the killing. All three suspects maintain their innocence.

At issue for Knox's defense is a minuscule amount of victim Kercher's DNA found on the blade of a knife that has Knox's DNA on the handle and which investigators believe to be the murder weapon.

Gino has said that the amount of DNA found on the knife was too sparse to be reliably attributed and said that it could also possibly have been the result of an inadvertent contamination in the police lab.

"DNA does not have wings, but it flies," Gino said. "In a laboratory where hundreds of samples are examined, the risk of contamination exists and should be taken into consideration."