Last Updated 6:28 p.m. ET
PERUGIA, Italy - American student Amanda Knox, who was convicted by an Italian court for the 2007 murder of her roommate Meredith Kercher, was acquitted Monday by an appeals court.
Her murder conviction in the 2007 slaying of her roommate Meredith Kercher was thrown out by the jury, and she was ordered immediately released from prison after nearly four years of detention. She was seen leaving the prison about 90 minutes later.
Italian lawmaker Rocco Girlanda, who has spearheaded Knox's case and is close to the American, says she and her family will leave Italy on Tuesday aboard a commercial flight from Rome.
Knox collapsed in tears after the verdict was read out.
The murder conviction against her former boyfriend Raffaele Sollecito was also thrown out.
The judge upheld Knox's conviction on a charge of slander for accusing bar owner Diya "Patrick" Lumumba of carrying out the killing. He set the sentence at three years - meaning for time served - and a fine of 22,000 euros (about $29,000). Knox has been in prison since Nov. 6, 2007.
Knox and Sollecito had been convicted in 2009 of sexually assaulting and murdering Kercher, who was stabbed to death in her bedroom. She was found the following day in a pool of blood and covered by a duvet.
Knox was sentenced to 26 years in prison, Sollecito to 25. Also convicted in separate proceedings was Rudy Hermann Guede, an Ivorian man. They all denied wrongdoing.
DNA evidence used to convict Knox and Sollecito has since been scientifically discredited.
Inside the courtroom, Knox's parents, who have regularly traveled from their home in Seattle to Perugia to visit the 24-year-old over the past four years, hugged their lawyers and cried with joy.
"We're thankful that Amanda's nightmare is over," her younger sister Deanna Knox told reporters outside the courthouse. "She suffered for four years for a crime she did not commit." She then asked for privacy for the family so they could "recover from this horrible" ordeal.
"We've been waiting for this for four years," said one of Sollecito's lawyers, Giulia Bongiorno.
The Kercher family looked on grimly as the verdict was read out by the judge after 11 hours of deliberations by the eight-member jury.
The Kercher family looked on grimly and a bit dazed as the verdict was read out by the judge after 11 hours of deliberations.
"We respect the decision of the judges but we do not understand how the decision of the first trial could be so radically overturned," the Kerchers said in a statement. "We still trust the Italian justice system and hope that the truth will eventually emerge."
"We want to keep her memory alive," she said after the verdict.
Outside the courthouse, competing protesters - some supporting Knox, some not - added their voices, with cheers as well as shouts of "Shame, shame!"
As the verdict was announced, about a dozen supporters from the group called Friends of Amanda, gathered at a downtown Seattle hotel to watch the proceedings on TV, burst into applause and cheered. They began chanting, "She's free!" and "We did it!"
Earlier Monday, as hundreds of reporters and cameras filled the underground, frescoed courtroom, Knox tearfully told the Italian appeals court she did not kill her British roommate, pleading for the court to free her so she can return to the United States. The court began deliberations moments later.
Knox frequently paused for breath and fought back tears as she spoke in Italian to the six members of the jury and two judges in a packed courtroom, but managed to maintain her composure during the 10-minute address.
"I've lost a friend in the worst, most brutal, most inexplicable way possible," she said of the 2007 murder of Meredith Kercher, a 21-year-old Briton who shared an apartment with Knox when they were both students in Perugia. "I'm paying with my life for things that I didn't do."
"She had her bedroom next to mine, she was killed in our own apartment. If I had been there that night, I would be dead," Knox said. "But I was not there."
"I did not kill. I did not rape. I did not steal. I wasn't there. I wasn't there at the crime," Knox said.
"48 Hours Mystery" correspondent Peter Van Sant reports that Knox appealed to the jury - members of which wept openly during her statement - to reverse the conviction and let her return home.
"I insist I'm innocent and that must be defended. I just want to go home, go back to my life," she told the court through tears.
Van Sant says Knox's words brought tears even to the eyes of some journalists in the room.
Minutes before, an anxious Sollecito also addressed the court to proclaim his innocence and plead for his release from prison.
"I never hurt anyone, never in my life," Sollecito said, shifting as he spoke and stopping to sip water. He said at the time of the murder he was in a great period of his life, close to defending his thesis to graduate from university and having just met Knox.
The weekend Kercher was murdered was the first the pair planned to spend together "in tenderness and cuddles," he said.
At the end of his 17-minute address, Sollecito took off a white rubber bracelet emblazoned with "Free Amanda and Raffaele" that he said he was been wearing for four years.
"I have never taken it off. Many emotions are concentrated in this bracelet," he said. "Now I want to pay homage to the court. The moment to take it off has arrived."