out in which gangsters free Danny  Leggett, was based upon the famous "Kansas City Massacre" in which  gunmen attacked FBI agents and policemen as they were transporting  federal prisoner Frank "Jelly" Nash on June 17th, 1933. In real  life, one agent, three policemen and Nash himself were killed. As  shown in the film, this was incident that increased the power of the  FBI and turned into the agency it is today. The other incident was  the shoot