The Killer Is on the Phone (1972)
A woman whose husband was murdered five years previously, is stalked by his killer, who wants to eliminate her as a potential witness. What he doesn't know is that the shock of his murder caused her to have amnesia, and she doesn't remember anything.
Directed by: Alberto De Martino
Starring: Telly Savalas, Anne Heywood, Osvaldo Ruggieri, Giorgio Piazza, Willeke van Ammelrooy, Rossella Falk
Links: IMDb, Movie posters, Movie stills