Lawyers for Amanda Knox's ex-boyfriend made a final appeal to Italy's top criminal court Friday to overturn the pair's murder conviction for the 2007 slaying of Knox's roommate, saying there were errors of "colossal proportions" in the guilty verdict.

Attorney Giulia Bongiorno dissected the 2014 Florence appeals court decision to show what she called errors of fact and logic that resulted in prison sentences of 28 1/2 years for Knox and 25 years for Raffaele Sollecito in the death of 21-year-old Meredith Kercher.

Judges at the high Court of Cassation began deliberating shortly after noon, and a decision could come late Friday. A decision to confirm the convictions could result in an extradition request for Knox, who is currently free in the U.S.

In her closing arguments, Bongiorno said even Knox's original statement to police -- which was never entered as evidence and was later changed -- exonerated her client.

Knox, who along with Kercher had been studying in the university town of Perugia, had initially accused a Congolese bar owner of the murder. She also told investigators that she was home the night that Kercher was killed and had to cover her ears to drown out her screams.

Bongiorno said she believed Knox's statement was coerced -- but that even if the high court chooses to consider it, Sollecito figures nowhere in her story.

"My heart is crying because I think she was pressured by an intermediary," Bongiorno said, apparently referring to the person who served as Knox's unofficial translator during police questioning. But within that statement, Bongiorno added, Knox "rules out Sollecito."

Kercher, a 21-year-old student from Britain, was found dead Nov. 2, 2007, in the apartment that she shared with Knox and two other students. Her throat was slashed and she had been sexually assaulted.

Knox and Sollecito were arrested a few days later. They both have maintained their innocence.

Initially Sollecito said he was working on his computer all night, and that he couldn't remember if Knox had stayed the whole night with him. Police said there was no sign he used the computer that night.

The couple later said they had spent the evening together at Sollecito's place watching a movie, smoking marijuana and making love.

Knox said her initial statement was forced under duress during late-night questioning by Italian police without a lawyer present and in a language she barely spoke. Her false accusation against Diya "Patrick" Lumumba, who owned the bar where Knox occasionally worked, resulted in a slander conviction against Knox that has been upheld on appeal.

The high court has several options as it weighs the case: It can confirm the guilty verdicts, raising the question of extradition for Knox; overturn the convictions and order a third appeals trial; or overturn the convictions without a new trial, tantamount to acquittal.

Knox, who was freed in 2011 after an earlier appeals court acquitted her, was awaiting the decision in Seattle.

One of her attorneys, Luciano Ghirga, said he had spoken with her but that she responded in only "monosyllables."

"She is very worried and stressed," Ghirga told reporters outside the courtroom. "She just answers by saying `Yes, no, thank you, talk to you later."'

Sollecito was in court Friday, joined by his girlfriend, sister and father, as was Lumumba.

Knox and Sollecito were initially convicted by a Perugia court in 2009, acquitted and freed in 2011, and convicted in 2014 in Florence after the Cassation court overturned the acquittals and ordered a new appeals trial.