An attorney for Jay-Z says he has obtained a videotape that will prove the rapper was not involved in the stabbing of record executive Lance "Un" Rivera last week. "It clearly established from my point of view that he didn't do it," Jay-Z attorney Murray Richman said Friday. "It shows the fight in the background and our client not being involved." Richman would not say how the tape was obtained. Jay-Z, who was honored as Rap Artist of the Year at the Billboard Music Awards on Wednesday night, was arrested Dec. 2 on charges of stabbing Rivera at a party in New York City. Rivera, who founded the Untertainmant label with the late Notorious B.I.G., is recovering after being hospitalized. Police could not be reached immediately to comment on the alleged tape.