He never had one.He made his "rep" as a writer by being someone who "knows" the criminal element in NYC,and who has "special" insights into how they think. The last article I read of his was back in the 60's,and he was supposedly writing about a arsonist he knew who was "mobbed up". His story was such obvious bull that I was shocked a paper would print it.
BTW,all his underworld "contacts" are various people he meets in bars. Now,we ALL know that nobody you meet in a bar would ever tell you a lie,right?