Mario Bava is a genius. This is the root of all giallo before The Bird with the Crystal Plumage and it stars John Saxon as Dr. Marcello Bassi and Leticia Roman as Nora Davis, a young girl who travels to Rome only to witness murder after murder. No one believes her because there’s no corpse. And it only gets worse for her.

Nora was in Rome to help her sickly aunt, who dies the first night that she’s in the city. After walking to a hospital to alert Bazzi, Nora is mugged. When she awakens, she watches a man pull a knife from a woman’s back. The police think she’s an alcoholic and send her to a sanitarium, where she’s rescued by Bazzi.

One of her aunt’s friends, Laura (Valentina Cortese), goes on vacation, allowing Laura to stay in her home. But our detective fiction obsessed heroine can’t resist snooping, finding a series of articles about a serial killer that the press are calling the Alphabet Killer, as he or she kills in alphabetic order. The last murdered person was Laura’s sister, but that was ten years ago. That’s when the phone rings and a voice tells her that “D is for death” and how she will be the next victim.

Nora begins to fall from the doctor and after they tour the city, she gets a phone call that leads them to an empty room with a recorded message telling her to leave the city if she wants to live.

The giallo conventions that we know and love originate here: a foreigner who can’t remember every detail of a murder, now in danger from the killer and unable to be helped by the police, causing them to turn to their own detective skills. Red herrings abound. And the killer seems to be one person, only for their identity to come out just before the end of the film. What is missing are the more psychosexual and high fashion parts of the genre, but don’t worry. They’ll soon show up in force.

The film was the least commercially successful picture of Bava’s career, as giallo films didn’t find favor until Argento’s 1970’s efforts. It was released in the United States by American International Pictures as Evil Eye, part of a double bill with Black Sabbath. This version features a different score and more of an emphasis on comedy.

You can watch this movie on Shudder.