A convicted child murderer has taken the stand at the appeals trial of Amanda Knox, claiming he has information clearing the American student of killing her roommate.

Knox was convicted of murdering Meredith Kercher, a British student in Perugia, and sentenced to 26 years in prison, while co-defendant Raffaele Sollecito was sentenced to 25 years. Also convicted in separate proceedings was Rudy Hermann Guede, an Ivorian man. They all deny wrongdoing.

Witness Mario Alessi was held in the same prison as Guede, and claims Guede had confided in him that Knox and Sollecito are innocent.

Alessi, called by Sollecito's defense, said Saturday that Guede made the claim in Nov. 2009 during recreation time at the Viterbo prison. Guede denies that.