Puzzle of Horrors (1969)

John Alexander’s wife, Helen, has left him for her lesbian lover. As she speeds away from their mansion for the last time, her Jaguar explodes and she is killed. As the weeks pass, police detectives begin to suspect Helen’s death to be murder with John as a prime suspect. Still devastated by the loss, John slips into a deep depression until he views a recently made lesbian porn film that appears to feature his dead wife! He becomes obsessed with finding the woman in the film and his search propels him into the sleazy porno underworld of drugs and mobsters, with the police detectives one step behind him.