Italy court to call sex-murder retrial or close mystery case

Italy's top court will rule Tuesday on whether US student Amanda Knox should face a retrial over the murder of her British housemate or whether to close the case for good, despite unanswered questions about a second mystery killer.

Knox and her Italian former boyfriend Sollecito were originally 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.

Judges were expected to rule on whether to uphold a 2012 prosecution appeal to reinstate the convictions against Knox and Sollecito on Monday. Unexpectedly however, they sought more time for deliberations, pushing the decision back to Tuesday.

The postponement of the ruling until 0900 GMT appeared to spark unease among lawyers representing the former lovers at the Rome court. Sollecito's lawyer Giulia Bongiorno said the delay was "rare... and hard to interpret."

Prosecutors addressing the court Monday said they were convinced the former lovers were guilty of murdering Kercher. They called for the judges to "make sure the final curtain does not drop on this shocking and dire crime."

The defence argued that errors in DNA evidence had seen Knox and Sollecito wrongly accused from the start and called for their acquittal to be upheld.

Should the prosecution's request be granted on Tuesday however, Knox and Sollecito could face a re-trial in Florence, though Knox would likely be tried in absentia.

The Seattle student returned home immediately after her release and the United States does not normally extradite its citizens 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 in November 2007.

A third person, Ivory Coast-born drifter Rudy Guede, who like the other two has always denied the murder, is the only person still in prison for the crime.

Prosecutors had alleged that Kercher was killed in a drug-fuelled sex attack involving Knox, Sollecito and Guede. They had said that it was the American student who delivered the final blows while the other two held the victim down.

But the appeals judge quashed the convictions of Knox and Sollecito in 2011, largely over the admissibility of DNA evidence. The judges said the murder remained "unsolved" because it must have been carried out by more than one person.

Kercher's family insists that 47 knife wounds on Meredith and the apparent use of two different knives in the attack meant that more than one killer was involved -- which means that the second murderer is still at large.

In her first interrogation following the murder, Knox said -- without a lawyer or an interpreter present -- that 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 blamed her initial comments on exhaustion and police coercion.

The supreme court is also set to rule Tuesday on Knox's appeal against a slander conviction for having fingered the bar owner, who was held in a cell for two weeks based on her allegations.