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 US citizen of murdering her British roommate and freed her to return home to the United States.

Knox left prison outside Perugia on Monday night, less than two hours after the verdict was read out in a packed court acquitting her and her Italian former boyfriend of the brutal murder. Knox was expected to leave Italy on Tuesday for the US. Her whereabouts were unknown.

Knox thanked those "who shared my suffering and helped me survive with hope", in a letter to a foundation that seeks to promote ties between Italy and the US and which has always championed her cause.