Bribery in the NYC pistol licensing department
He'd get $5-25,000 to expedite permit issuance. He told an undercover officer that "the officer could earn $900,000 if he helped with an estimated 150 permits."
Sounds like he was stiffing the other licensing branch officers: they said they were only getting $100 per permit.
Bribery of the permit-issuers has been an issue at least since the Knapp Commission investigated NYPD corruption in the 1970s. As I recall, that led to moving the decision making from officials in the precincts to officials at headquarters, in the hopes that would make corruption a little more difficult. There was probably undocumented corruption since the system began--you can find news articles from the 1920s and 1930s about mobsters holding pistol carry permits.
UPDATE: this fellow paid $12,500 and got a pistol carry permit, despite having a felony record. He was shocked to find that he still couldn't buy a gun, since he flunked the NICS background check.