38. Brigid O'Shaughnessy
Played By: Mary Astor
Movie: The Maltese Falcon (1941)
Noir women don't just resort to murder as a way to quickly sever a relationship—it's more like their first course of action. For most of Maltese Falcon, Brigid O'Shaughnessy plays it straight and true with P.I. Sam Spade (Humphrey Bogart). But as it turns out, she had a bigger hand in the inciting incident than she initially let on.