The Black Vampire (1953)

A man is on trial as being the serial killer of adolescent girls in Buenos Aires, the question not whether he is the killer which is a given, but whether he should be held responsible for his actions which would dictate how the justice system would deal with him. Flashbacks then show the events around the killings primarily from three different but intersecting perspectives. One is the official investigation led by prosecutor, Dr. Bernard. On evidence, he believes the killer is like a vampire, leading to the perpetrator being referred to as the Black Vampire within the public mindset: compelled, for whatever reason, to kill girls, but feeling remorse after the fact in being unable to control those urges. Dr. Bernard's lonely home life which entails caring for his invalid wife colors the way he approaches the investigation. Two is the killer himself, milquetoast Teodoro Ulber, a private English teacher whose feelings of inadequacies as a man are a result of being ridiculed his entire life by women. And three is Amalia Keitel, a singer working under the stage name Rita at a seedy nightclub which is frequented by Ulber as a "friend" of Amalia's colleague Cora, and which is already on the authorities' radar as being a drug den. Through the window just outside her dressing room, Amalia caught a brief glimpse of the killer dumping the body of the first victim, Amalia initially reluctant to report what she saw, despite it affecting her emotionally, in the primary goal of protecting her own adolescent daughter from publicly being connected to someone like "Rita".