This French serial killer movie is based on fact but an intertitle at the start tells us that it is also a work of 'imagination'. It's the kind of film the Americans do better but it has a clammy quality nevertheless and revealing the killer in the opening minutes actually adds to the tension and it's well acted and it's well directed by Cedric Anger. For reasons that will become clear very early on it concentrates very much on the police investigation while at the same time giving us a good, detailed psychological portrait of the killer. Unfortunately the film doesn't appear to have had much of a distribution so it's very possible it passed you by.