A Black Veil For Lisa (aka La Morte Non Ha Sesso) (1968)

Set in Germany, a narcotics detective (John Mills) is insanely jealous of his sexy younger wife (Luciana Paluzzi) and it's beginning to affect his job. Meanwhile, he's attempting to track down a drug lord but all his contacts get killed before they can talk! Directed by Massimo Dallamano, this movie is often erroneously referred to as a giallo which it's definitely not even though there are some brutal murders. A crime thriller would be a more accurate description, it's not a mystery as the killer is revealed quite early in the film. If it had been made in the 1940s in B&W, it would be film noir with Mills as the poor doomed patsy and Paluzzi as the calculating femme fatale. John Mills gets to bring a lot of shading to his besotted policeman, much more than is usually displayed in such pulp which I suppose is what attracted him to the unlikely (for him) role. With Robert Hoffmann as the hit man who's not as clever as he thinks.