A tearful Amanda Knox has said she is \"overwhelmed\" at being back on US soil after her acquittal for the murder of UK student Meredith Kercher in Italy.After landing at Seattle, she thanked all those who had supported her. Knox, 24, and ex-boyfriend Raffaele Sollecito, 27, were on Monday cleared on appeal of the 2007 killing, having spent nearly four years in jail.The family of Leeds University student Miss Kercher, 20, from south London, say their fight for justice continues. Speaking at Seattle International Airport, Knox joked that she had to be reminded to speak in English, rather than Italian, before telling reporters: \"I\'m really overwhelmed right now.\'Believed in me\'\"I was looking down from the airplane and it seemed like everything wasn\'t real. Thank you to everyone who has believed in me, who has defended me, who has supported my family.\" She added that she was just looking forward to spending time with her relatives.Her parents, Curt Knox and Edda Mellas, praised the family\'s supporters and legal team to the assembled media. Ms Mellas said: \"It\'s because of the letters, calls and amazing support we have received from all over the world - and especially in Seattle - that we have been able to endure and make sure Amanda had the support she needed.\"The family\'s lawyer, Theodore Simon, had earlier described the family\'s situation as a \"gruelling, four-year, nightmarish marathon that no child or parent should have to endure\". \"Meredith was Amanda\'s friend. Amanda and the family want you to remember Meredith and keep the Kercher family in your prayers,\" he added.Members of the Kercher family held a press conference on Tuesday in Perugia, where Miss Kercher was studying at the time of her death.Her brother, Lyle, said they accepted the court\'s decision to acquit Knox and Mr Sollecito. However, he said: \"We are now left looking at this again and thinking how a decision that was so certain two years ago has been so emphatically overturned, which raises other questions.\"It feels very much like back to square one. The search goes on to find out what really happened.\"His sister, Stephanie, added: \"Until the truth comes out, we can\'t forgive anyone because no-one\'s even admitted to it knowing there was someone out there who was responsible.\"An eight-member jury cleared both defendants of Miss Kercher\'s murder after doubts were raised over procedures used to gather DNA evidence.The judge upheld Knox\'s conviction for slander for accusing bar owner Patrick Diya Lumumba of carrying out the killing. But he set the sentence at three years, time that Knox has already served, meaning she was free to leave.During a separate earlier trial, Rudy Guede was convicted of Miss Kercher\'s murder for his role in the killing and sentenced to 30 years in prison. On appeal, his conviction was upheld but his sentence reduced to 16 years. A lawyer for Guede said on Tuesday he would seek a retrial.It was said in court that Guede did not act alone - raising questions following the acquittals as to who had also been at the murder scene.The prosecution, which maintains Miss Kercher was killed in a brutal sex game which went wrong, is to appeal to Italy\'s highest court over the acquittals.However, it appears unlikely that Knox would be extradited back to Italy from the US. Mike Heavey, a friend of the Knox family, told the BBC she would need time to assimilate to normal life.\"It\'s going to be very difficult but Amanda is amazingly effervescent and resilient.\"Knox would probably re-enrol at the University of Washington to finish her degree, he said.Meanwhile, fellow member of the Friends of Amanda Knox group Jim Lovering said she was likely to wait a month or two before giving her full account of the ordeal.She would have to sell her story to pay off debts accrued by her family in fighting her case, he added.