“Let’s make a film about a child murderer,” Fritz Lang suggested in 1930 to his wife and collaborator, Thea von Harbou. Nearing 40 and already the celebrated director of the classic German films Die Nibelungen (1924), The Woman in the Moon (1926) and Metropolis (1927), Lang yearned to work on a smaller, more intimate scale. He wanted to tell the story of a real human being rather than the mythic figures of Siegfried and Die Kriemhilds Rache, the larger-than-life characters of Dr. Mabuse: The Gambler (1922) or the archetypal constructs of Metropolis. Turning to the Berlin newspapers, Lang found the news was all bad. Reports of robbery, rape and murder filled the pages from front to back. Lang began to think about what drives a man to kill and reflected on recent accounts of what we know refer to as serial murder.

In Sielesia in 1924, Karl Denke was arrested for the murder of dozens of tramps and travelers. Among the boxes of human bones and vats of pickled flesh clogging "Papa" Denke’s Stawowa Street home, authorities found a ledger in which the killer had recorded the names of his victims, their body weights and the dates of their deaths. In Hannover, Fritz Haarman had gone after young boys, whose bodies he dismembered and whose flesh he sold as beef, while hotdog vendor Karl Grossman hunted women in Berlin, killing and dismembering more than two dozen prostitutes before his capture in 1921. As Lang did his research at police headquarters on Berlin’s Alexanderplatz, the crimes of Peter Kürten were making big headlines all over Germany. The dapper and courteous Kürten derived extreme sexual gratification from strangling, stabbing and hacking at his victims, sometimes two at a time. The epicenter of his fury fell between February and November of 1929. With his arrest the following year, Kürten became a media darling, his crimes piquing the interest of a nation who dubbed him “The Vampire of Düsseldorf.”

Lang was intrigued by the little known fact that, before Kürten’s capture, Berlin’s criminal underworld had actually conspired to help the police bring him to ground – so disruptive were his murders to the hustle and flow of professional criminal activity. This bit of true crime trivia gave Lang the seed for what would eventually be known as M (1931), his first sound picture. Lang and von Harbou cowrote the script for what was then called Die Mörder sind unter uns (“The murderers among us”). The scenario hewed closely to the facts of the Kürten case (although it was finished before the man's arrest): When the hunt for a killer of young children brings unwanted police attention to Berlin’s criminal underworld, the gangsters, thieves, pickpockets, pimps and beggars join forces to find the murderer themselves. To play his child killer, Lang chose theater actor Peter Lorre. Born László Löwenstein and raised (like Lang) in Vienna, Lorre was a mentee of Bertolt Brecht, who thought so highly of the actor that he wrote angry rebuttals to newspaper critics denigrating Lorre’s performances. Only 5’5” in height and blessed (or cursed) with oversized, haunted eyes, Lorre was the perfect choice to play the tormented Hans Beckert. Heard before he is seen, Beckert is introduced via his shadow as he whistles “In the Hall of the Mountain King,” from Edvard Grieg’s Peer Gynt. A little known fact about this classic moment of German cinema is that Peter Lorre, for all his talents, could not whistle. While editor Paul Falkenberg and Thea von Harbou both gave the task a try, it fell to the tonedeaf Lang to dub the disconcerting ditty.

M ends in a protracted criminal tribunal, in which Hans Beckert is tried for his crimes by a jury of his underworld peers and is allowed to speak in his own defense. Knowing that Lorre’s tendency was to go so deeply into his characters that he would manifest physical symptoms, Lang exploited his star by pushing him over the emotional edge while encouraging the extras to pull no punches in their on-camera abuse of the actor. Shooting this sequence at Berlin’s Staaken Zeppelinhalle (an aircraft hangar converted for use as a soundstage) lasted from 8:00 in the morning through the entire day and evening and didn’t end until after midnight, at which point Lorre is reported to have fainted from exhaustion. (It is also purported that Lorre himself performed the stunt of Beckert being dragged down a flight of stairs inside a burlap bag, a bit of business that was printed only after two dozen takes.) Watching the film even today, it’s difficult to know whether it is Beckert telling his accusers or Lorre pleading with a director he had come to despise “… I can’t… I can’t go on. Can’t go on… Can’t go on… Can’t go on.” Although starring in M had nearly killed him, the part of Hans Beckert was the role of a lifetime for Peter Lorre, who would enjoy considerable success stemming from his association with the part but was also cursed by typecasting that relegated him too often to the cinematic ghetto of cheap horror films.

M had its premiere on May 11, 1931. It was another media event, with the sidewalks and streets surrounding the cinema jammed with pedestrians queuing up for tickets and automobiles idling immobile in traffic. Less than two months later, Peter Kürten paid for his sins under the blade of the guillotine. The movie inspired by the horror he wrought was a huge success that solidified Fritz Lang’s standing as Germany’s greatest director. Ironically, within two years after completing this study of human psychopathy and mob mentality, both Lang and Lorre were forced to flee Germany as National Socialist Workers Party kingpin Adolf Hitler was elected German Chancellor. Both Lang and Lorre decamped first to Paris (where French moviegoers finger-pointed Lorre on the street, calling him Le Maudit – “the Damned One” – after M’s French release title) and eventually wound up in Hollywood. Lorre died at the age of 60 in 1964, while Lang lived considerably longer, passing away in 1976. Though he had once derided his M director as a sadist, Lorre posed for pictures with Lang and laughed with him on the occasion of a special screening of the film at UCLA in the early 1960s. “By then,” Lang’s biographer, Patrick McGilligan wrote, “these fossils of the Weimar age apparently had some to accept their shared past.” Given all they’d been through since they had made their one film together, both men likely understood that there are monsters… and then there are monsters.