By Deepa Babington
PERUGIA, Italy (Reuters) - Prosecutors demanded on Friday that an Italian court throw out an appeal by American student Amanda Knox against her conviction for murdering a British housemate in a drug-fueled sex game, saying it must ignore an "obsessive" media campaign.
The courtroom in the central Italian town of Perugia was packed for the final stages of Knox's appeal in a sensational case that has grabbed headlines in Italy, Britain and the United States.
Knox, 24, looked pale and nervous as she was ushered into a courtroom besieged by television cameras and curious onlookers in the historic university town where Meredith Kercher's semi-naked body was found in a pool of blood in 2007.
Knox, who has been in jail for nearly four years, including the period before her first trial, was sentenced in 2009 to 26 years in prison and her Italian ex-boyfriend Raffaele Sollecito to 25 years for the murder. Both say they are innocent.
Knox listened impassively as prosecutors began closing arguments by trying to discredit a forensic report that had bolstered the Seattle native's case.
"When you decide, I want you all to feel a bit like the parents of Meredith Kercher, a quiet and serious young woman whose life was cut short by these good kids from good families," prosecutor Giancarlo Costagliola told the jury.
"There has been an almost obsessive media campaign from the press and television that has made all viewers feel a bit like the parents of Amanda and Raffaele, two youths from good families held in prison because of a dogged prosecution."
Knox's hopes of being set free were a strong boost by an independent report earlier this year that cast major doubt on DNA evidence used to convict her, and also cited bungling by police scientists.
But prosecutors urged the jury to look past the confusion in the case, maintaining that Kercher's blood was on a knife handled by Knox that was identified as the murder weapon and that Sollecito's DNA was found on Kercher's bra clasp.
Both pieces of police evidence were rejected by the independent forensic experts.
Friday's hearing began with a rare appearance by Perugia's chief prosecutor to express support for the case against Knox.
A verdict is expected after concluding arguments from both prosecution and defense at the end of next week, nearly four years after the murder stunned Italy and shook Perugia's image as an idyllic student town in the Umbrian countryside.
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.
Her 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 stop it.
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.
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.
(Editing by Barry Moody and Mark Heinrich)