Italy's highest court of appeals was set to rule Monday on whether US student Amanda Knox, acquitted in 2011 of murdering her British housemate in the university town of Perugia, will face another trial.
The court was due to decide whether to uphold a 2012 prosecution appeal to reinstate the convictions against Knox and her former boyfriend Raffaele Sollecito.
Knox and Sollecito had initially been sentenced to 26 and 25 years in prison for killing and sexually assaulting Meredith Kercher in 2007, but were acquitted on appeal after four years in prison.
Prosecutor general Luigi Riello told the supreme court on Monday that the acquittal was "a rare mix of violation of the law and illogicalness and should be overturned".
"I believe all the premises are there to make sure the final curtain does not drop on this shocking and dire crime," he said, adding that the judge who acquitted Knox and Sollecito "lost his way".
The prosecution, which filed the appeal last year on behalf of Kercher's family, insists the acquittal, which was based mainly on the admissibility of DNA evidence in the case, contained "omissions and many mistakes".
The court will base its ruling on points of law rather than a re-examination of the evidence.
The lawyers for Knox, Sollecito and Kercher attended the hearing, along with Sollecito's father.
Knox "is anxious and waiting for the decision. She would love to come back to Italy, as an innocent and free person," Luciano Ghirga, the American's lawyer, told reporters outside the court.
Should the prosecution's request be upheld, Knox and Sollecito could face a re-trial in Florence, though Knox would likely be tried in absentia.
The Seattle student returned to her home town immediately after her acquittal and the United States does not normally extradite its citizens abroad to face legal action.
Kercher, 21, was found half-naked with her throat slashed in a pool of blood in her bedroom in the house that she shared with Knox on November 2, 2007.
Her body was covered with knife wounds and bruises and investigators found traces of a sexual assault.
A third person, a local Ivory Coast-born drifter named Rudy Guede, who like the other two has always denied the murder, is the only person still in prison for the crime.
The appeals judge who freed Knox and Sollecito in 2011 said the killing remained "unsolved" because investigators insist it must have been carried out by more than one person.
Kercher's family have called for answers, insisting that 47 knife wounds on Meredith and the apparent use of two different knives in the attack meant that more than one killer had been involved.
Prosecutors had alleged that Kercher was killed in a drug-fuelled sex attack involving Knox, Sollecito and Guede and had claimed that it was the American student who delivered the final blows to the victim while the other two held her down.
Knox was painted by her accusers as a seductive "she-devil" who had an unhealthy obsession with sex, while her defence insisted she was simply a naive girl-next-door, a yoga lover whose nickname "Foxy Knoxy" referred to her childhood football skills.
In her first interrogation following the murder, Knox said she was in the house at the time and falsely identified the owner of a bar where she worked as a waitress as the killer.
She later said that she was with Sollecito at his house all night and that her initial comments were misunderstood and only given after heavy questioning.
Sollecito also changed his story under questioning, but both students later blamed exhaustion and police coercion for their contradictory statements, which were made without lawyers present.
The key to the appeal was an independent analysis of two pieces of evidence that had helped convict Knox and Sollecito -- a kitchen knife and Kercher's bra clasp.
The review cast serious doubt on the original analysis, with experts and video evidence pointing to sloppy practice among the police at the crime scene and possible contamination of the evidence.
Both the original trial and the appeal were accompanied by sensational tabloid headlines, shocking exposes and international television coverage which critics warned was influencing the court.
The blue-eyed Knox has written a memoir on her ordeal, due to be published in April by HarperCollins.