Ernst Gennat

It was solely by Gennat's efforts that a homicide squad was eventually created, which earned him promotion to lieutenant inspector (at the age of 45).

Building on early forensic science as established by Hans Gross, he was among the first to recognize the importance of the exact preservation of evidence at crime scenes.

Up till then, it had been common practice for the first policemen at a crime scene to start by “cleaning up the mess” or arranging the corpse in a decorous, reverent manner.

Gennat drew up precise guidelines for crime scene procedures and established the inviolable principle forbidding anyone from touching or changing anything until the investigators had arrived.

For the immediate work at the crime scene there were materials for securing evidence and steel marking posts with sequential numbers; everything from searchlights to diamond cutters and axes.

The systematically structured card file comprised not just capital offences but also the categories "indirect or cold murder" (suicide following defamation or false accusations), "existential destruction through malicious deception" (suicides provoked by scammers, frauds, obscure fortune tellers or marriage impostors) and "existential destruction through blackmail".

He was lauded in particular for his persistency and perseverance, his phenomenal memory, and the enormous psychological empathy which already enabled him to practise what came to be termed "criminal profiling" forty years later.

Moreover, it was Gennat (not Robert Ressler) who coined the term "serial killer" in his 1930 article "Die Düsseldorfer Sexualverbrechen" (on Peter Kürten).

Being aware of the effect of capital offences on the public and of the opinion-forming role of the press, he strived to harness for the purposes of investigative work.

Beyond his dry Berlin humour and the numerous witticisms and anecdotes circulating about him, Gennat's striking corpulence (he weighed an estimated 21.3 stone, or 270 lbs) also contributed to no small degree to making the "Big Guy from the homicide squad" a famous character.

Ernst Gennat inspired the fictional character inspector Karl Lohmann who appeared in Fritz Lang's M (1931) and The Testament of Dr. Mabuse (1932).

German actor Udo Samel plays Gennat in the second and third seasons of the TV show Babylon Berlin, which is based on Volker Kutscher's historical crime novels featuring inspector Gereon Rath.