American student Amanda Knox is an innocent victim who was wrongly convicted of killing her British roommate in a "tragic judicial case," her defence lawyer told the appeal trial in closing arguments Thursday in Italy.

Carlo Dalla Vedova, noting that Knox has spent 1,000 days behind bars after she was convicted in 2009 of killing British fellow student and roommate Meredith Kercher, said errors in analyzing DNA were made that led to Knox's conviction.

"It's possible that there's been a mistake. No one is infallible," he told the court in the university town of Perugia.

The lawyer also told the jury 'that the only possible decision to take is that of absolving Amanda Knox," and the court had already seen "there is no trace of Amanda Knox in the room where murder took place."

'Knox has been crucified in a public square, subjected to the most sinister of speculations.'—Carlo Dalla Vedova, defence lawyer

The defence lawyer is one of three slated to give arguments Thursday. Judge Claudio Pratillo Hellmann said there will be no verdict until after defendant statements on Monday.

Knox, from Seattle, was arrested in 2007, four days after the body of 21-year-old Kercher was found in their apartment. She was convicted of murder and sentenced to 26 years in prison, while co-defendant Raffaele Sollecito, now 26, was sentenced to 25 years. Knox and her former boyfriend are appealing.

Hundreds of reporters, cameramen and photographers have descended on the central Italian town as jurors move toward a verdict.

Knox's family has flown in for the last stretch of the trial, attending hearings and visiting her in prison. Members of the Kercher family, which has kept a lower profile, are also expected to come to Perugia for the verdict.

"We visited her yesterday [Wednesday] and she was rather anxious, but it was also the first time all my four daughters have been together for two years," said a teary-eyed Curt Knox, the defendant's father.

Knox 'crucified in a public square,' lawyer says

Knox's original trial heard that Kercher's death was the result of a drug-fuelled sex session that also involved Sollecito, and went terribly wrong. Kercher's half-naked body was found in a pool of blood in the apartment.

Prosecutors allege that Knox led the sexual assault of Kercher and slit her throat with a knife.

The role of the media in Knox's conviction and appeal has been criticized by both sides.

Prosecutor Giuliano Mignini lamented what he said was media interference and an increasingly strong campaign in support of Knox.

Defence lawyers said Thursday that Knox had been unfairly portrayed.

"Knox has been crucified in a public square, subjected to the most sinister of speculations," Dalla Vedova said. "All, regardless of their nationalities, have offended Amanda Knox."

Case has 'swept away' Knox's life: lawyer

Dalla Vedova said Knox was a "girl who has had a tsunami, a tornado hit her. This has swept away her life."

He urged the court not to be afraid to recognize that the lower court that had convicted the two had made a mistake.

Prosecutors say that a fourth person was present the night of the murder, Rudy Hermann Guede from Ivory Coast, who has also been convicted. Italy's highest criminal court has upheld Guede's conviction and his 16-year prison sentence.

Guede denies wrongdoing, but has exhausted all levels of appeals under Italy's judicial system.

Knox and Sollecito insist they spent the night at his house.

Key in the case is the review of DNA evidence that the defence maintained was unreliable and possibly contaminated. The prosecution and forensic investigators disagree with that view.

With files from The Associated Press