(CBS/AP) PERUGIA, Italy - An Italian court rejected a prosecutor's request Wednesday for new testing of crucial DNA evidence in the appeals trial of Amanda Knox. This is a positive development for the American student seeking to overturn her conviction in the murder of her British roommate.
The decision was a blow to the prosecution, especially in light of an independent review -- as sought by the defense -- which found that much of the original forensic evidence used to convict Knox was unreliable and possibly contaminated.
Without a clear motive or convincing witnesses in the case, the DNA evidence is crucial to the prosecution and much of the appeals outcome likely hinges on it.
A police official, Patrizia Stefanoni, who conducted the original investigation in the Amanda Knox case, told the appeals court Tuesday there was no contamination on crucial pieces of evidence linking Knox and co-defendant Rafael Sollecito, Knox's then-boyfriend, to the murder.
Judge Claudio Pratillo Hellmann, who is presiding over the appeal, said the discussion had already been thorough enough for the court to form an opinion. New testing would be "superfluous," he said, rejecting the request made earlier in the day by Prosecutor Manuela Comodi.
The court also rejected another prosecution request to put back on the stand a witness who had previously testified that his brother, a fugitive, had killed Kercher during a botched burglary. The witness, a jailed Naples mobster named Luciano Aviello, announced he wanted to retract and was questioned by Comodi in prison in July. The court ruled that transcriptions of that questioning would suffice.
Knox and co-defendant Sollecito were convicted in 2009 of sexually assaulting and killing her British roommate Meredith Kercher in the apartment that Knox and Kercher shared while studying in Perugia.
Knox is serving a 26-year prison term, but denies wrongdoing.
Rudy Guede, an immigrant from the Ivory Coast and small-time drug dealer, was also convicted in connection to Kercher's murder. He was originally jailed for 30 years, but the sentence was later cut to 16 years.
The court set closing arguments to begin Sept. 23, with the prosecution going first, followed by civil plaintiffs and the defense. A verdict is expected by the end of September.