Amanda Knox acquittal in murder of Meredith Kercher thrown out by Italian high court Updated at 7:35 a.m. ROME Italy's highest criminal court on Tuesday overturned the acquittal of Amanda Knox in the slaying of her British roommate and ordered a new trial, prolonging a case that has become a cause celebre in the U.S. The Court of Cassation ruled that an appeals court in Florence must re-hear the case against the American and her Italian-ex-boyfriend for the murder of 21-year-old Meredith Kercher. The exact issues that have to be reconsidered won't be known until the court releases its full ruling. Lawyers for Knox and her ex-boyfriend Raffaele Sollecito looked grim as they huddled with prosecutors and court officials to get details after the ruling was issued. Lawyers for the Kercher family said they had got what they wanted. Kercher's body was found in November 2007 in her bedroom of the house she shared with Knox and others in Perugia, an Italian university town where the two women were exchange students. Amanda Knox comes home to America Amanda Knox personal photos Prosecutors alleged Kercher was the victim of a drug-fueled sex game gone awry. Knox and Sollecito denied wrongdoing and said they weren't even in the apartment that night, though they acknowledged they had smoked marijuana and their memories were clouded. An Ivory Coast man, Rudy Guede, was convicted of the slaying in a separate proceeding and is serving a 16-year sentence. Knox and Sollecito were also initially convicted of the murder and given long prison sentences, but were then acquitted on appeal and released. The high court's ruling Tuesday overturns the appeals court acquittals. "We are completely back to square one," said CBS News legal analyst Jack Ford, who notes that in the U.S. justice system, this third trial would not be possible as an appeals court's decision is final -- not so in Italy, as proven by the high court's move on Tuesday. Italian law cannot compel Knox to return from the U.S. for the new trial. The appellate court hearing the case could declare her in contempt of court but that carries no additional penalties. It is unclear what would happen if she was convicted in a new appeals trial. "If the court orders another trial, if she is convicted at that trial and if the conviction is upheld by the highest court, then Italy could seek her extradition," Knox's lawyer Carlo Dalla Vedova said Monday. It would then be up to the United States to decide if it honors the request. U.S. and Italian authorities could also come to a deal that would keep Knox in the United States. David Marriott, a spokesman for the family, released a statement on behalf of Knox moments after the Italian court's ruling on Tuesday: It was painful to receive the news that the Italian Supreme Court decided to send my case back for revision when the prosecution's theory of my involvement in Meredith's murder has been repeatedly revealed to be completely unfounded and unfair. I believe that any questions as to my innocence must be examined by an objective investigation and a capable prosecution. The prosecution responsible for the many discrepancies in their work must be made to answer for them, for Raffaele's sake, my sake, and most especially for the sake of Meredith's family. Our hearts go out to them. No matter what happens, my family and I will face this continuing legal battle as we always have, confident in the truth and with our heads held high in the face of wrongful accusations and unreasonable adversity. CBS News correspondent Mark Phillips says there is code in that statement; Knox's legal team has always alleged the prosecution bungled the investigation. Meredith Kercher Kercher's family, on the other hand, welcomed the Italian high court's decision on Tuesday. "There are still questions that are unanswered and we are all looking to find out the truth," Meredith Kercher's sister Stephanie told CBS News partner network Sky News in Britain. We welcome the decision that a retrial has been ordered and are pleased it is a step forward to finding an answer to some of those questions. Knox, now 25, and Sollecito, who turned 29 on Tuesday, were arrested shortly after Kercher's body was found in a pool of blood. The appeals court that acquitted them in 2011 criticized virtually the entire case mounted by prosecutors. The appellate court noted that the murder weapon was never found, said that DNA tests were faulty and that prosecutors provided no murder motive. After nearly four years behind bars in Italy, Knox returned to her hometown of Seattle and Sollecito resumed his computer science studies, following the degree he successfully earned while studying in prison. Knox is now a student at the University of Washington, according to her family spokesman, Dave Marriott. Italy's judicial system allows for two levels of appeals, and prosecutors can appeal acquittals. Although the court on Monday heard gruesome details, including how Kercher choked on her own blood, it wasn't ruling on the guilt or innocence of the defendants. Its sole task was to decide if the appellate trial was properly conducted. Details of the ruling weren't issued Tuesday and won't be for several weeks.