Sergio Gobbi made several criùe thrillers in the late sixties and early seventies, all kinds of crime films. Very different one from the other. This one is adapted from a Boileau Narcejac's novel. I have not read it, so I don't know if it is faithful to the genuine material or not, but it is a good film, tough not a masterpiece, nothing to do with an Alfred Hitchcock's movie, or even a Claude Chabrol's one. Because this story could easily have been made by Chabrol. Gobbi hied here some of his usual actors: Robert Hossein, Albert Minski. Not my favourite from him, I prefer LE TEMPS DES LOUPS. But, I repeat, this one is intriguing enough to be seen.