Fritz Lang has shown that he is a great director and in the movie called M released in 1931 he showed his talent when it comes to telling a story.
Peter Lorre plays Hans Beckert and he is the only notable actor in this mega popular movie. Someone is abducting children in Berlin and they have no idea what is happening. That is the beginning of the movie and it is leading us into a story that has a potential to become one of the best ones in the history of movies. The murderer gives kids candy and other items that kids like and that is how he is luring them...
The murderer is sending the letters to the newspapers and that is basically the only lead that the police have about him. There is a blind beggar in the story and he is the only witness, but you can see what the problem is in his case... The killer bought a balloon from him when he wanted to murder one of the kids and that is why the police are questioning him in order to find out who the killer is.
In the M movie, you can see the police and the criminals chasing the murderer, but the thing is that they don't have the same goal...