Fritz Haarmann (1879 – April 15, 1925) was a notorious serial killer born in Hanover, Germany.

From 1919 to 1924, Haarmann committed at least 24, possibly many more murders. His accomplice, Hans Grans, sold the clothing of his victims, otherwise not being involved in the murders. Haarmann's victims were young male vagrants who hung around railway stations, whom Haarmann would lure back to his apartment and then kill them by biting through their throats in a kind of sexual frenzy. Rumours had it that Haarmann would then peddle meat from the bodies of his victims as black market pork, but there was no evidence.

Haarmann was eventually apprehended when numerous skeletal remains, which he had dumped into the river Leine, washed up. His trial was very spectacular; it was one of the first major media events in Germany. There were no concepts or expressions for his unthinkable deed--he was called a "werewolf", a "vampire" and a "sexual psychopath" at the same time. But apart from the cruelty of what Haarmann had admittedly done, even more scandalous--shaking society at the very core--was the involvement of the police in the case: Haarmann cheated on thieves and dealers and was close friends with some of the officers, who occasionally took clothes as "gifts" and looked away.

Haarmann was beheaded, though it was not entirely clear if he would rather have to be locked up in an asylum for being in a state of diminished responsibility. But public opinion was heated and would not have approved of Haarmann just being locked away. Haarmann was found guilty and executed, even though serious doubts about his state of mind remained. Grans received a twelve-year sentence. What became of him after his release is not known.

Haarmann became known as "The Butcher of Hanover." A film titled The Tenderness of the Wolves was released in Germany in 1973 dramatizing Haarmann's crimes. It starred Kurt Raab as the killer and featured Rainer Werner Fassbinder in a minor role. A big success was the film entitled Der Totmacher (The Dead Maker; 1995), starring Götz George as Haarmann. It was based on the protocols of the psychiatric examinations of Haarmann by Erich Schultze, one of the main psychiatric experts in the trial.

Maria Tartar: Lustmord. Sexual Murder in Weimar Germany. Princeton UP, 1995. Thomas Kailer: Werewölfe, Triebtäter, minderwertige Psychopathen. Bedingungen von Wissensgenerierung. Der Fall Haarmann. In: Carsten Kretschmann (Hg.): Wissenspopularisierung. Berlin 2003, S. 323-359.