Un Bianco vestito per Marialé

A young girl named Mariale witnesses her father murder two lovers before shooting himself in the head. We then fast forward some years and a grown up Mariale is living in a mansion with her husband Paolo. She has mental problems and is often given drugs to quell the problem. She invites a group of friends to stay at the house with her and her husband, but the party soon degenerates into an orgy and it's not long before the guests are being picked off one by one. (imdb)