Italian Supreme Court judges have heard the arguments, now they must decide whether to order American Amanda Knox to stand trial for a second time in the death of her former roommate.
The judges concluded a hearing into the question early Monday afternoon, and were expected to announce their decision soon.
Knox spent four years in jail before an appellate court overturned her murder conviction in the 2007 death of Meredith Kercher. She returned to the United States in 2011. Prosecutors say that despite the appellate decision, they still believe Knox and her former boyfriend, Raffaele Sollecito, are responsible for the death.
"We are still convinced that they are the co-authors of Meredith's homicide," Italian news agency ANSA quoted Perugia, Italy, prosecutor Giovanni Galati as saying.
Knox, who is not in Italy for the hearing, is confident in the Italian legal system and hopes one day to return to Italy as a free woman, her lawyer, Luciano Ghirga, said Monday.
If the acquittal is overturned, the case will go back to an appellate court and Knox might have to return to Italy. If she refuses, the Italian government could appeal to the U.S. government for her extradition.
But even if it does, Knox still not might end up before an Italian court.
U.S. officials might reject such a request because it violates the U.S. legal principle that a criminal defendant can't be tried twice on the same allegation, said Joey Jackson, a contributor for HLN's "In Session."
Italy lacks the absolute prohibition present in U.S. law preventing authorities from retrying a criminal defendant who has been acquitted of a charge.
"We have principles that are well-founded within our Constitution, one of which is double jeopardy," he said. "So as a result of that, I think it would be highly objectionable for the United States to surrender someone to another country for which justice has already been administered and meted out. So I don't think or anticipate that that would happen."
The case began in 2007, after Knox moved to Perugia to study at the University for Foreigners of Perugia for one year
Knox, then 20, shared a room with British student Kercher, 21.
That November, Kercher's semi-naked body was found at the home, with her throat slashed.
Police arrested Knox and Sollecito, who was her boyfriend at the time.
Two years later they were convicted of murder, but were cleared when they appealed the verdicts in 2011.
Another man, Ivorian drifter Rudy Guede, was convicted separately of Kercher's killing.
Guede admitted having sexual relations with Kercher but denied killing her.
In legal paperwork published in December 2011, the judge in the case wrote that the jury had cleared the pair of murder for lack of evidence proving they were guilty.
Knox's family said last year the appeal was unwelcome, but no cause for concern.
"The appeal of Amanda's acquittal by the prosecution was not unexpected as they had indicated from the day of the verdict that they would appeal," a family statement in February 2012 said.
Knox has spent the last year and a half trying to resume a normal life, studying at the University of Washington in Seattle, her hometown.
She has written a book on her ordeal, titled "Waiting to be Heard," which will be published next month.
Francesco Sollecito, father of Raffaele, told CNN in a phone interview last year that the family was "not happy about the decision (to appeal). My son is trying to get back to normal life."
"We can do very little in this situation," he said, but as Italian citizens, they would have to accept the court's decision.
"We hope that the high court will finally put the words 'the end' to this story."