A back-seat crewman on the Marine jet that sliced an Italian gondola cable--killing 20 people--testified that he was asked by the pilot and navigator what to do with a videotape shot during the flight. "I said I'd get rid of it," Capt. Chandler Seagraves said at the court-martial of Capt. Richard Ashby at Camp Lejeune, N.C. Seagraves, who testified under immunity, was the main witness against Ashby, who is charged with obstruction of justice and conspiracy for helping his navigator get rid of the personal tape. The government rested its case.