By Deepa Babington
PERUGIA, Italy (Reuters) - Amanda Knox's appeal against her murder conviction enters its final stages on Friday, with an emboldened defense hoping the American student will walk free after nearly four years in an Italian prison.
Closing arguments in the appeal hearing begin on Friday in the university town of Perugia, where Knox was convicted of murdering her British housemate Meredith Kercher in 2007 during a frenzied sex game that got out of control.
Kercher, from Surrey, England, was found lying semi-naked in a pool of blood with her throat slit in her apartment in Perugia, where she was doing a year of overseas study.
An Italian court in 2009 sentenced Seattle-native Knox to 26 years in prison and her Italian ex-boyfriend Raffaele Sollecito to 25 years.
Rudy Guede, an Ivorian drifter with a criminal record, was also sentenced in October 2008 to 30 years in jail for taking part in Kercher's murder. All three say they are innocent.
Knox's fresh-faced good looks and the gory sex-and-blood twists and turns in the case have riveted audiences in Britain and the United States, where Knox has been perceived by some as a victim of blundering Italian police.
Others have portrayed the 24-year old -- dubbed "Foxy Knoxy" in the press -- as a marijuana-smoking party girl who shopped for lingerie with her boyfriend days after the murder.
Knox's story has been made into a movie for U.S. television starring Hayden Panettiere, though lawyers for both Knox and the victim's family have tried to halt the film.
Knox's case for release was bolstered by a forensic report this year saying DNA evidence used in the trial was unreliable and numerous errors had been made by police scientists.
Forensic experts said there was no evidence to support the original police conclusion that Kercher's blood was on a knife handled by Knox that was identified as the murder weapon.
A verdict from the appeal hearing is expected next week.
If acquitted, both Knox and her ex-boyfriend would be freed immediately, said Carlo Fiorio, a professor of criminal procedure at the University of Perugia. They could also have their sentences confirmed, shortened or lengthened, he said.
"The two defendants can still appeal in a final court in order to try and repeal the verdicts of both the murder trial and appeals hearing," he added.
(Additional reporting by Eleanor Biles; Editing by Kevin Liffey)