|The Mephisto Waltz (1971) [Myles Clarkson]: Dies after his spirit switches bodies with Bradford Dillman; since it's Alan's spirit that dies in Bradford's body, I'm listing the scene for both actors. (Thanks to Stephen)
The Glass House (1972) [Jonathon Paige]: Shot in the chest by Clu Gulager when Alan comes running through the prison door, trying to get away from Vic Morrow.
Kill Me If You Can (The Caryl Chessman Story) (1977) [Caryl W. Chessman]: Executed in the gas chamber.
Murder at 1600 (1997) [National Security Advisor Alvin Jordan]: Shot in the chest by a Secret Service agent when Alan points a gun at Ronny Cox. (Thanks to Derek)