Photo: Peter Lorre played the serial killer in “M”.
M is supposedly based on the real-life case of serial killer Peter Kürten, the “Vampire of Düsseldorf”, whose crimes took place in the 1920s, although Lang denied that he drew from this case.
“At the time I decided to use the subject matter of M there were many serial killers terrorizing Germany — Haarmann, Grossmann, Kürten, Denke,” Lang told film historian Gero Gandert in a 1963 interview.
In 1930, when Lang placed an ad in the newspaper stating that his next film would be Mörder unter uns (Murderer Among Us) and was about a child murderer, he immediately began receiving threatening letters in the mail.
He was also denied a studio space to shoot the film at Stakken studio.
When Lang confronted the head of Stakken studio to find out why he was being denied access to the studio, the studio head informed Lang that he was a member of the Nazi party and that the party suspected that the film was meant to depict the Nazis.
This assumption was based entirely on the film’s original title and the Nazi party relented when informed of the film’s plot.
M was eventually shot in six weeks at a Stanken Zeppelinhalle studio just outside of Berlin. Lang also made the film for Nero-Film instead of UFA or his own production company.
It was produced by Nero studio head Seymour Nebenzal, who later produced Lang’s The Testament of Doctor Mabuse.
Other titles given to the film before “M” were Eine Stadt sucht einen Mörder (A City searches for a Murderer) and Dein Mörder sieht Dich an (Your Killer Looks At You).
While researching for the film Lang spent eight days inside a mental institution in Germany and met several real child murderers, including Peter Kürten.
He later used several real criminals as extras in the film and eventually 25 cast members were arrested during the film’s shooting.
Peter Lorre was cast in the lead role of Hans Beckert, the mentally ill child murderer.
During filming, Lorre acted in the film during the day while appearing onstage in Valentine Katayev’s Squaring the Circle at night.
Lorre’s character whistles the tune “In the Hall of the Mountain King” from Edvard Grieg’s Peer Gynt Suite No. 1.
However, Peter Lorre himself could not whistle – it is actually Lang’s wife and co-writer Thea von Harbou who is heard.
The film was one of the first to use a leitmotif, associating “In the Hall of the Mountain King” with the Lorre character.
Later in the film, the mere sound of the song lets the audience know that he is nearby, off-screen.
This association of a musical theme with a particular character or situation, a technique borrowed from opera, is now a film staple.