Legendary director Fritz Lang took a gamble when making M, which tells the story of a child murderer in Berlin, as the film has been credited with forming two different genres: the serial killer movie and the police procedural. I don't know what Lang's personal feelings of Germany were at that time, but the images in M were angry, vile, and extremely grotesque. It was as if Lang knew there was something brewing deep beneath the surface of German society, an evil that he felt he needed to express. Most of the sequences in M are of dirty smoke-filled conference rooms, disgusting dives, and corrupt unmoral men committing secret conspiracies in the shadows. The German people Lang casted in the film were highly unattractive caricatures, as if they were some part of a sick decaying society, greatly reminding me of the demonic faces of the accusing judges in Carl Dreyer's silent The Passion of Joan of Arc.
M was Lang's very first sound film and that new instrument is brilliantly put to use right from the very first frame, as you hear on the soundtrack the disturbing chant of a children's elimination game being played in a Berlin courtyard. That scene is immediately followed by a heartbreaking sequence involving a mother pathetically waiting for her little girl to return home from school, all the while the mother frantically calls out her daughter's name, while Lang cuts to images of an empty dinner plate, her daughter's ball rolling through a patch of grass and the balloon that was bought for her ensnared in some telephone lines. Sound is also brilliantly used when implicating the presence of the killer, especially by hearing him compulsively whistling the tune from Peer Gynt over and over again, until the notes stand in for the murders. And yet Lang's sparingly use of sound has never been better put to use then it had in the thrilling conclusion of the film, when actor Peter Lorre, (In one of his first screen performances) gives one of the greatest speeches in all of film history.