( CNN ) -- Italy 's supreme court on Tuesday explained its earlier ruling that American Amanda Knox be retried in the 2007 death of her roommate , saying the jury that acquitted her did n't consider all the evidence , and that discrepancies in testimony need to be answered . The high court also said evidence could support prosecutors ' initial argument -- that Meredith Kercher was killed in a twisted sex misadventure game at Kercher and Knox 's home in Italy , the high court said , according to Italian news agency ANSA . The appeals court jury that acquitted Knox and her ex-boyfriend , Raffaele Sollecito , in 2011 `` neglected significant evidence '' and theories , the high court said in a 74-page explanation . Knox and Sollecito 's retrial , which could start as soon as the fall , should examine discrepancies in testimony , the high court said . These include differing witness accounts of when screaming could be heard from the home , ANSA reported . The high court overturned the acquittals in March , but withheld its full reasoning until Tuesday . Kercher , a 21-year-old British exchange student , was found stabbed to death in November 2007 in the villa she rented with Knox , then 20 , in the central Italian university town of Perugia . Knox : Sometimes I ca n't stop crying . Knox and Sollecito were arrested that year and convicted in 2009 of murder in Kercher 's death , but the jury overturned the conviction in 2011 . Knox then returned to her home city of Seattle , Washington . In legal paperwork published in December 2011 , the judge in the case wrote that the jury had cleared the pair of murder for lack of evidence proving they were guilty . Another man , Ivorian drifter Rudy Guede , was convicted separately of Kercher 's killing . Guede admitted having sexual relations with Kercher but denied killing her . Francesco Maresca , attorney for Kercher 's family , appeared satisfied after reading the high court 's reasoning Tuesday . The ruling `` represents a very harsh judgment of the appeal trial , '' Maresca said . An attorney for Knox said that he respects the ruling but he does n't agree with it . The high court , he said , was supposed to consider only the legitimacy of the appeal but instead attempted to re-examine the whole case . `` This means that we are going to do again a trial that has already been done , a trial in which there is no clear evidence , '' attorney Carlo Della Vedova said . Knox may be ordered to return to Italy for the retrial . If she refuses , the Italian government could appeal to the U.S. government for her extradition . But even if it does , it 's not clear whether the United States would extradite her . When asked Tuesday if Knox would return to Italy to face the new trial , Della Vedova replied : `` Would you send your kid back ? ''
Italian high court : Evidence could support a sex-game theory . Comment: Knox was convicted in 2009 for a stabbing death in Italy , but was acquitted in 2011 . The high court ordered a retrial in March , and released its reasons Tuesday .