Fritz Haarmann — The Butcher of Hanover

Fritz Haarmann was a German serial killer who murdered at least 24 young men and boys in Hanover between 1918 and 1924, earning the nicknames "The Butcher of Hanover" and "The Vampire of Hanover." He killed most of his victims by biting through their throats and is believed to have sold their flesh as black market meat during a time of severe food shortages in post-WWI Germany. Haarmann worked as a police informant, which helped him avoid detection and approach victims. He was arrested in 1924 after human bones were found near the River Leine, convicted of 24 murders, and guillotined in April 1925.