Updated at 7:55 a.m. Eastern
PERUGIA, Italy - Amanda Knox on Tuesday thanked those Italians who supported her throughout her four years of prison, a day after an appeals court cleared the young American of murdering her British roommate and freed her to return home to the United States.
Knox left her prison outside Perugia Monday night, less than two hours after the verdict was read out in a packed court acquitting her and her Italian one-time boyfriend of the brutal murder.
The Italy-US Foundation, which has championed Knox's cause, said the American was at Leonardo da Vinci airport in Rome boarding a flight to London, where she will catch a connecting flight to the United States.
AP photographers and camera crew at Leonardo da Vinci airport in Rome saw Knox family members in a terminal. Knox was not immediately seen, and was believed to have been escorted by police through a non-public entrance to the airport."She just couldn't wait to get on the plane. She told me that, even though she wasn't yet on the plane, she felt like she was already flying." Knox's friend Giulia Alagna tells "The Early Show."
"She was just very, very happy to get on that flight," added Alagna, who spoke to her friend on the phone as she waited to board her flight Tuesday morning. She said Knox's voice sounded "strong" in spite of her ordeal.
The freed American thanked those "who shared my suffering and helped me survive with hope," in a letter to the foundation, which seeks to promote ties between Italy and the United States.
"Those who wrote, those who defended me, those who were close, those who prayed for me," Knox wrote. "I love you, Amanda."
Knox and her ex-boyfriend Raffaele Sollecito were convicted in 2009 of sexually assaulting and murdering Meredith Kercher, a 21-year-old British student who shared an apartment with Knox in Perugia. Knox was convicted to 26 years, Sollecito to 25.
In a stunning reversal, the appeals court in Perugia overturned those convictions and set the two free. They had been in prison since Nov. 6, 2007, four days after Kercher's body had been found at the apartment.
The prosecutor in the case announced Tuesday morning that he would appeal the acquittal to Italy's highest court, but that process won't begin until the appeals court issues a complete explanation as to how it arrived at Monday's decision.
The 24-year-old Knox dissolved into tears as the verdict was read in a packed courtroom after 11 hours of deliberations, and needed to be propped up by her lawyers on either side. (Click player at left to see Knox's tearful appeal to court)
Two hours later Knox was in a dark limousine that took her out of the Capanne prison just outside Perugia, where she had spent the past four years, and headed to Rome.
"During the trip from Perugia to Rome Amanda was serene," said Corrado Maria Daclon, the secretary general of the Italy-US Foundation, who was with Knox in the car. "She confirmed to me that in the future she intends to come back to our country."
The prosecution's case was blown apart by a court-ordered DNA review that discredited crucial genetic evidence used to convict the two in 2009.
While waves of relief swept through the defendants' benches in the courtroom, members of the Kercher family, who flew in for the verdict, appeared dazed and perplexed. Meredith's older sister Stephanie shed a quiet tear, her mother Arline looked straight ahead.
There was little joy Tuesday for the Kerchers as Knox and her family put Italy behind them, reports "48 Hours Mystery" correspondent Peter Van Sant.
Speaking at a hotel in Perugia Tuesday morning, Kercher's brother said the family felt as though they had been thrown back to "square one" after Knox and Sollecito's acquittal.
"That's the biggest disappointment, not knowing still," said Meredith's sister Stephanie Kercher at the news conference. "Knowing that there is obviously someone, or people, out there who have done this."
The Kercher family stressed that they respected the court's decision, and they wouldn't want anyone innocent spending time behind bars for no reason.
The Kerchers had pressed for the court to uphold the guilty verdicts passed two years ago, and resisted theories that a third man convicted in the case, Rudy Hermann Guede, had acted alone. Guede, convicted in a separate trial, is serving a 16-year sentence.
The verdict reverberated through the streets of this medieval hilltop town, where both Knox and Kercher had arrived with so much anticipation for overseas studies programs four years ago.
Hundreds of mostly university-age youths gathered in the piazza outside the courtroom jeered as news of the acquittals spread. "Shame, shame," they yelled, adding that a black man had been made to shoulder all of the guilt for the murder.
The jury upheld Knox's conviction on a charge of slander for accusing bar owner Diya "Patrick" Lumumba of carrying out the killing. But the judge set the sentence at three years, less than the time Knox had spent in prison.
Prosecutors said they would appeal to the nation's highest criminal court, after reading the court's reasoning due out within 90 days.
"Tonight's sentence is wrong and confounding," prosecutor Giuliano Mignini told the ANSA news agency. "There is a heavy conviction for slander. Why did she accuse him? We don't know."
Just before deliberations began Monday, Knox tearfully told the court she did not kill her roommate.
"I've lost a friend in the worst, most brutal, most inexplicable way possible," she said of the 2007 murder of Kercher, 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."