The Glass Tomb (1955)

'Pel' Pelham is a veteran carnival barker who's happily married and desperately wants a good education for his young son. With money borrowed from bookie Tony Lewis, he persuades Sapolio, a professional "starving man," to attempt to break his own world's record of 65 days without food. Pel, a natural promoter, persuades a real estate broker to donate land for the show, which will feature Sapolio inside a glass cage housed in a tent to be ogled by the curious paying public. Prior to the start of the ordeal, Sapolio and his wife throw a party in their flat. When a girl in an upstairs apartment is murdered, suspicion falls on Pel and Tony Lewis, the girl's former boyfriend. Sapolio unknowingly has glimpsed the murderer, but initially cannot remember what he looked like. That makes "The Starving Man" a target for the real killer.