Amanda Knox and two others were convicted of killing British student Meredith Kercher in November 2007, but evidence in her appeals process indicated DNA evidence used to convict them might have been contaminated.
"There is no conclusive scientific evidence regarding the nature of the blood," said a report by forensic experts said of alleged DNA found on a knife recovered from the home for Knox's former boyfriend, Raffaele Sollecito.
Knox's attorney, Luciano Ghirga, said his client is much calmer since her appeals process began, the Italian news agency ANSA reported Friday.
"It's the first time that someone believes me," Ghirga said Knox told him.
Her response followed Wednesday's testimony that earlier police findings were "not sustainable."
The 145-page report also highlighted "erroneous findings" in previous reports tracing DNA on the victim's bra strap to Sollecito.
"After four years of darkness, there's a glimmer of light," said Sollecito from prison.
Sollecito and Ivorian Rudy Guede were convicted with Knox in the killing. Prosecutors said the death involved sex games gone awry.
The trio has always maintained their innocence. The court will discuss the report's findings July 25.