Friedrich Heinrich Karl "Fritz" Haarmann (25 October 1879 – 15 April 1925) was a German serial killer, known as the Butcher of Hanover, the Vampire of Hanover and the Wolf-Man, who committed the sexual assault, murder, mutilation and dismemberment of a minimum of 24 boys and young men between 1918 and 1924 in Hanover, Germany.
Haarmann was found guilty of 24 of the 27 murders for which he was tried and sentenced to death by beheading in December 1924.
In addition, in accordance with German practice, his honorary rights of citizenship were revoked.
He was subsequently executed in April 1925.
Haarmann became known as the Butcher of Hanover (German: Der Schlächter von Hannover) due to the extensive mutilation and dismemberment committed upon his victims' bodies and by such titles as the Vampire of Hanover (der Vampir von Hannover) and the Wolf-Man (Wolfsmensch) because of his preferred murder method of biting into or through his victims' throats.