An appeals court in Perugia, Italy overturned the murder conviction of Amanda Knox on Monday night. Knox, an American student who has served four years in prison for the murder of her roommate, openly sobbed after the judge delivered the decision.

The Associated Press reports that a court-ordered review of crucial DNA evidence discredited the prosecution’s case, eventually leading the appellate committee to acquit Knox and her former boyfriend, Raffaelle Sollecito, of sexual assault and murder. Knox asserted her innocence to the jury in fluent Italian while holding back tears on Monday afternoon. Around 10 pm the presiding judge ordered the defendants’ immediate release.

The dramatic scene was fitting of the trial, which has attracted international media coverage since 2007, and Knox is expected to return to her home in Seattle as early as Tuesday.  The prosecution has promised to appeal to the Court of Cassation, Italy’s highest appellate for criminal cases.