Gunsmoke. June 12, 1954. CBS net. "The Cover Up". Sustaining. Barnaby Hoffer plans to kills Art Long, but both of them are found dead! It looks like Sam Baxtin did it! The script was used on the Gunsmoke television series on January 12, 1957. William Conrad, Georgia Ellis, Joseph Kearns, Clayton Post, Roy Rowan (announcer), Howard McNear, Parley Baer, Norman Macdonnell (director), Rex Koury (composer, conductor), John Meston (writer), Helen Kleeb, Paul Savage.