Murder Capital explores Prohibition-era Madison, Wisconsin. Per capita, Madison was the most violent and deadly city in the United States during the 1920s. Along with the usual suspects (bootleggers), Madison was unique in its strong Ku Klux Klan presence. In the background was a prominent judge, overseeing Mafia cases by day, but by night taking illegal loans from these very same criminals. In effect, he tied his own hands and the violence was allowed to continue unabated.