Peter Kürten was a German serial killer, known as "The Vampire of Düsseldorf" and the "Düsseldorf Monster", who committed a series of murders and sexual assaults between February and November 1929 in the city of Düsseldorf. In the years before these assaults and murders, Kürten had amassed a lengthy criminal record for offences including arson and attempted murder. He also confessed to the 1913 murder of a nine-year-old girl in Mülheim am Rhein and the attempted murder of a 17-year-old girl in Düsseldorf.

Ernst August Ferdinand Gennat was director of the Berlin criminal police. He worked under three political systems in his 30-year career as one of the most gifted and successful criminologists in the German Reich. His caseload included those of Fritz Haarmann and Peter Kürten.