One of the masterpieces of classic German cinema.
There isn't much that can be said about this film that almost everyone hasn't already said or written. It is one of the great films of German cinema, one of the best productions that were made before the Second World War and one of the best films in the career of the renowned director Fritz Lang, who shortly afterward would leave Germany due to the rise of Nazism, refusing to deal with that political regime.
The film is inspired by real events, namely the murderous path of Peter Kürten, the “Vampire of Düsseldorf”, who terrorized people at the same time and also had young teenagers as his victims. The film manages to capture very well the feeling of fear that existed among the people of the city and the attempts that the police made to find this merciless killer.
The cinematography, in black and white, still shows signs of the influence of German expressionism without, however, giving up the realism that the entire film demanded. In fact, I can't say whether the film was inspired by “noir” or came to inspire “noir” later, but I could see the aesthetic and style similarities. Peter Lorre is the only actor who stands out: he brought the main role to life and shines without almost having to say anything. It's an excellent work by the actor and has undoubtedly opened many doors for him.