No mystery at all here, except for how I managed to live nearly 60 years without ever hearing of this guy. It took 300 policemen to arrest him. It's like an Edward G. Robinson movie come to life.
My God Ginger, you are so close. Right movie studio (Warners), in the right period for films ("Golden age of talkies": 1927 - 1960), but wrong star of Warner's gangster films.
"Two Gun" Crowley's escapade with that massive shoot-out confrontation with 300 of New York's finest was the basis for the scene in "Angels With Dirty Faces" involving Jimmy Cagney confronting a similarly large number of New York police when hold up in a building, having taken Pat O'Brien hostage. The film is not based on Crowley's career (Cagney's character has it's better side, especially when dealing with the "Dead End" kids, and he may have pretended to turn yellow when being strapped into the electric chair (one of Cagney's most powerful scenes - done totally with shadows) to not become a hero to them. But the plot has little to do with Crowley's one-man crime wave, involving wounding and killing policemen. Cagney, by the way, got the New York Film Critics' Award for his performance in this film - his first major movie award.