Independent forensic experts have attacked key evidence used to convict US student Amanda Knox of the murder of her British housemate in Italy in 2007.
They told the court in Perugia that a knife believed to have been used to kill Meredith Kercher bore no trace of blood and may have been contaminated with other DNA.
Knox and her then-boyfriend Raffaele Sollecito were jailed for murder in 2009.
Presenting the findings from a report released last month, the experts also said police had used the same gloves for different samples of evidence.
Meredith, 21, was found half naked with her throat cut at the house she shared with Knox in Perugia, after what judges concluded was a sex game that had gone wrong.