Amanda Knox reacts to the verdict on Oct. 3, 2011.
ROME/AP - Italy's highest criminal court has overturned the acquittal of Amanda Knox in the slaying of her British roommate and ordered a new trial.
The Court of Cassation ruled Tuesday 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.
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Kercher's body was found in November 2007 in her bedroom of the house she shared with Knox and other roommates in Perugia, an Italian university town where the two women were exchange students. Her throat had been slashed.
Prosecutors alleged Kercher was the victim of a drug-fueled sex game gone awry. Knox and Raffaele Sollecito denied wrongdoing. An Ivory Coast man, Rudy Guede, was convicted of the slaying in a separate proceeding and is serving a 16-year sentence.
It was not immediately clear whether Knox would return to Italy for her re-trial, but legal experts have expressed doubts, and Italian law does not require her to do so. She returned home to the U.S. after her acquittal by an appeals court in October 2011.
Knox says it's "painful" to have her acquittal on murder charges overturned by Italy's highest criminal court but she's confident in the truth, and says remaining questions about her case must now be examined by objective and capable prosecutors.
Knox was initially convicted in 2009 of the crime and she had spent almost four years in an Italian prison by the time her conviction was overturned.