Some of the DNA traces used to convict American student Amanda Knox of murdering Briton Meredith Kercher may have been contaminated, independent experts say.
The review by two court-appointed experts was requested by the defence and has been eagerly awaited. Its conclusions could boost Knox's chances of overturning her murder conviction.
Knox was convicted in 2009 of sexually assaulting and murdering Miss Kercher, from Coulsdon, Surrey, - with whom she shared an apartment while both were exchange students in Perugia, Italy.
She was sentenced to 26 years in prison.
Her co-defendant and ex-boyfriend Raffaele Sollecito was also convicted and sentenced to 25 years.
Both have denied wrongdoing and are appealing.
Prosecutors maintained in the first trial that Knox's DNA was found on the handle of a kitchen knife they believe to be the murder weapon, and that Miss Kercher's DNA was found on the blade. They say Sollecito's DNA was found on the clasp of Miss Kercher's bra.
Those findings were disputed by the defence, and the appeals court granted an independent review.
The experts say in the report filed to the Perugia court today and obtained by The Associated Press that the genetic profile attributed to Miss Kercher is "unreliable" and cannot be attributed with certainty. They said results may have been contaminated on both the blade and bra clasp.
Regarding the blade, the experts said: "We believe that the technical tests are not reliable." The document said the tests did not conform to international standards and procedures. "It cannot be ruled out that the result obtained ... may stem from contamination," said the report's conclusions.
The experts reached a similar conclusion regarding the bra clasp.
The findings are likely to please the defence, which had long maintained DNA traces were inconclusive and that they might have been contaminated when they were collected and analysed.
The two experts - Stefano Conti and Carla Vecchiotti from Rome's Sapienza University - are to present their review in court next month.