Blood in Black Lace
Mario Bava - 1964
Also known as "Sei donne per l'assassino" or "Six Women for the Assassin," Blood and Black Lace is credited by critics as being the first giallo to introduce the masked killer with the shiny weapon, a cornerstone of giallos and later slasher movies. In this movie, the killer wears a featureless mask and a fedora, looking a bit like the Question.
Though the film is gory, it's highly stylized. The director, Mario Bava, took cues from Alfred Hitchcock when planning use of color, and also keeping in mind Psycho when making his victims half-naked women.
The film begins with the murder of a fashion model on the grounds of the fashion house by the faceless killer, and we come to find out that the fashion house she worked for was a den of crime, blackmail and drug smuggling. This first victim allegedly kept records of all the dirty dealings in her diary, a diary that gets passed around to all the other girls in the film. But once they have possession of the diary, the killer comes looking for them as well....