Powers Boothe died of natural causes in his sleep at his home in Los Angeles Sunday morning, according to his rep. The actor was 68.

Best known for his role as ruthless saloon owner Cy Tolliver on 'Deadwood', Boothe's career spanned theatre, TV and film, picking up an Emmy for 'lead actor in a limited series or special' for playing cult leader Jim Jones in ' Guyana Tragedy: The Story of Jim Jones' in 1980.

Other villainous roles included Senator Roark in 'Sin City', Vice-President and later President Noah Daniels on '24', and most recently Gideon Malick on 'Marvel's Agents of S.H.I.E.L.D.'.

His friend, actor Beau Bridges, tweeted the news Sunday afternoon: