Cause of death: cancer
Billy Dennis Weaver (June 4, 1924 – February 24, 2006) was an American actor and president of the Screen Actors Guild, best known for his work in television and films from the early 1950s until just before his death in 2006. Weaver's two most famous roles were as Marshal Matt Dillon's trusty deputy Chester Goode on the western Gunsmoke and as Deputy Marshal Sam McCloud on the police drama McCloud. He starred in the 1971 television film Duel, the first film of director Steven Spielberg. He is also remembered for his role as the twitchy motel attendant in Orson Welles's film Touch of Evil (1958).
Source : Wikipedia