Amanda Knox is released after winning appeal

Peter Popham in Perugia reports on a day of unbearable suspense

(PIER PAOLO CITO/AP)

She crumpled, then she wept, her lawyers' arms around her for support. To stifled cheers from supporters in an Italian courtroom, Amanda Knox and her former boyfriend Raffaele Sollecito were freed from jail last night after a jury quashed their convictions for the murder of British student Meredith Kercher.

Ms Knox, 24, appeared to struggle to remain standing as the judge read out the verdict that cleared her nearly four years after the body of the student was found in their shared apartment. She appeared dazed as guards rushed her from the court.

Outside, her younger sister Deanna Knox thanked the family's supporters, saying "their nightmare was over" and pleaded for privacy to try to rebuild their lives. Ms Knox and Mr Sollecito briefly returned to prison to complete paperwork. It was reported last night that Ms Knox is to leave Italy today.

The divisions of opinion were noisily evident outside the Perugia court, with Knox supporters cheering while dozens of local people, infuriated by the acquittal, screamed "Shame on you!" and "Assassins!" at lawyers coming out of the building.

The mother and two siblings of the victim of the murder also burst into tears in court, devastated by a judgment that came after a review cast serious doubts over the main DNA evidence linking the two to the crime.

Rudy Guede, the third person convicted of the murder, is serving a reduced sentence of 16 years for his role in the crime but has always denied responsibility for the murder, which many lawyers in court argued could only have been performed by more than one person.

Amanda Knox's three-year sentence for libelling Patrick Lumumba, a local man who she named as the killer during her interrogation, was upheld, but she has already served the time. She was also ordered to pay €21,000 (£18,000) to him in compensation. On all other counts the pair were ruled not guilty on the grounds of insufficient evidence. As had been widely predicted, the testimony of court-appointed scientists, who were scathing about sloppy police work, proved crucial. Prosecutors can appeal the acquittal to Italy's highest court, but there was no word last night if they planned to do so.

The jury's decision was the climax of an appeal which had elements of both a Hollywood premiere and a witch-burning, with hundreds of local people packed into the narrow piazza outside the court. "We've been waiting for this for four years," said one of Sollecito's lawyers, Giulia Bongiorno.

For the Kercher family the feelings were much more bitter. The victim's sister, Stephanie Kercher, in Perugia with her mother and brother, lamented that her sister "has been nearly forgotten". "We want to keep her memory alive," she said after the verdict.

In a statement released later, the family said: "We respect the decision of the judges but we do not understand how the decision of the first trial could be so radically overturned."

Ms Knox and her former boyfriend Mr Sollecito had told the court 12 hours earlier that they had nothing to do with the murder of Leeds University student Meredith Kercher. In pin-drop silence Ms Knox said that, with the death of Meredith, "I lost a friend in the most vile way imaginable."

In the weeks that followed, she said, she also lost her faith in the police. It was during an all-night interrogation that she admitted being in the house when the murder was committed. She withdrew the admission soon afterwards.

Mr Sollecito, fighting the same conviction, told the court that "I've never hurt anyone in my life" and that on the night of the murder he was "in a beautiful situation" with "beautiful, sunny, vivacious, sweet" Amanda. "We had been together for just a week," he said. "Our only desire was to spend the evening in tender embraces ... Our desire was to be apart from the world."

Speaking after him, Ms Knox told the court in Italian: "I'm paying with my life for something I did not do."

And she gave the court her version of the emotions she experienced after the discovery of Meredith's body, slashed to death in the flat they shared. "When we learned that Meredith had been killed, I couldn't believe it," she said.

Later in the day Meredith Kercher's mother Arline, her daughter Stephanie and son Lyle said they felt Meredith's suffering had been "hugely forgotten" in the enormous attention on Amanda and Raffaele's appeal.

Stephanie Kercher added: "Everyone needs to remember the brutality of what happened and everything she went through, the fear and the terror and not knowing why."

Q & A

Q: What does the verdict mean?

A: Yesterday's verdict represents the second of three levels in Italian criminal justice. Following a conviction, then a first appeal, either the defence or the prosecution is allowed to make a second and final appeal – to the Supreme Court of Cassation in Rome. The prosecution has said that it intends to do so. At this final level cases are heard only by judges and first appeal verdicts are only overturned on technical points.

Q: Who made it?

A: The appeal case was heard by a jury composed of six members of the public and two judges. A majority would have been enough to decide yesterday evening's verdict. The chief judge in an appeal has one vote – or two in the case of an even split – the assistant judge and the six lay members had one vote each.

Q: What happens now?

A: The Kercher family had denied that a US television network had put a private jet at the disposal of the Knox family to whisk her back to the US after she was freed. Italian prosecutors would then face the difficult task of extraditing Knox for a second appeal.

Q: What about the third suspect?

A: A third person, the unemployed drifter Rudy Hermann Guede, has already been convicted for his part in the murder, following separate, fast-track proceedings and appeals. His sentence is for 16 years.

Q: What was the evidence that the outcome hinged on?

A: Jurors in the original trial had heard the prosecution claim that DNA found on a knife allegedly used in the murder, and on the clasp of Ms Kercher's bra, indicated the pair's involvement in the killing. But expert witnesses employed for the appeal said that the tiny quantity of DNA available was not sufficient for reliable analysis. They also said there was no trace of blood on the knife identified as the murder weapon and that original forensic scientists made a series of glaring errors in collecting the evidence that might have caused serious contamination.

Q: What does Meredith Kercher's family think of the verdict?

A: They did not speak immediately after the verdict, though Meredith's mother's expression and slow, aided walk to the car suggested that they had been shattered by the decision.

The family had made it clear, through the lawyer, during the appeal process, that it was happy with the original conviction and that it was not looking for either Knox or Sollecito to go free. However, the family said yesterday that they acknowledged the right of the defendants to appeal.