The Boston Strangler (1968)
The Boston Strangler is a 1968 film based on the true story of the Boston Strangler and the book by Gerold Frank. It was directed by Richard Fleischer, and stars Tony Curtis as Albert DeSalvo, the strangler, and Henry Fonda as John S. Bottomly, the chief detective now famed for obtaining DeSalvo's confession.
More at Wikipedia.