Crime in general developed in parallel with prostitution in the city, beginning as petty thefts and other crimes linked to the need to survive in the war's aftermath. Berlin eventually acquired a reputation as a hub of drug dealing (cocaine, heroin, tranquilizers) and the black market. The police identified 62 organized criminal gangs in Berlin, called "Ringvereine". The German public also became fascinated with reports of homicides, especially "lust murders" or "Lustmord". Publishers met this demand with inexpensive criminal novels called "Krimi", which like the film noir of the era (such as the classic "M"), explored methods of scientific detection and psychosexual analysis.