ROME –  Italy's top criminal court says it threw out murder convictions against Amanda Knox and her former Italian boyfriend because there was absolutely no proof they were at the scene of her British roommate's slaying.

The Court of Cassation on Monday issued its formal written explanation, as required by Italian law, for its March ruling vindicating the pair once and for all in the legal battle over the 2007 murder of Meredith Kercher in Perugia, Italy.

The court wrote there was an "absolute lack of biological traces" of Knox, an American, or co-defendant Raffaele Sollecitio in the room or on the body of the victim. Slamming the quality of the prosecution's case, the court faulted the investigators for "blameworthy omissions of investigative activity."