PERUGIA, Italy - Being in prison is "very frustrating and mentally exhausting," a tearful Amanda Knox said Saturday, insisting that she is innocent of murdering her roommate and that does not want to spend the rest of her life behind bars.

The former exchange student briefly addressed the appeals court in Perugia, her voice breaking at times. The 23-year-old American is appealing her 2009 conviction for sexually assaulting and murdering British student Meredith Kercher, for which she received 26 years in prison.

The appeals court on Saturday set June 30 as a deadline for a key review of DNA evidence by independent forensic experts in the Knox case and allowed five new witnesses sought by the defense - all inmates in Italian prisons who claim they have information clearing Knox and her Italian codefendant, Raffaele Sollecito.

"I've spent more than 31/2 years in prison as an innocent person, and this for me is very frustrating and mentally exhausting," Knox said. "But nothing is more important than finding the truth after prejudices and many mistakes."

"I don't want to spend my whole life in prison as an innocent," she added.

Knox and Sollecito were arrested Nov. 6, 2007, a few days after Kercher's body, her throat slit, was found in the apartment she and Knox shared in Perugia. Sollecito, Knox's boyfriend at the time, was convicted of the same charges and sentenced to 25 years in prison.

The two have always denied wrongdoing, and much hinges on the review of DNA evidence used to convict them.

The trial will continue June 18 with the new testimony.