The FBN was framing people for chists sake you believe Vito Genovese would even utter a word or acknowledge a scumbag like Nelson Cantellops? The FAN was a rogue outfit run by Harry Anslinger who was enemy to Hoover. There were actual narc agents back than who were junkies themselves.FBN USED TO ILLEGAL TAP PHONES, HOUSES, payphone and collect illegal evidence than bust a mob guy on some bullshit PC.the case that put chin and Vito Genovese away also swept up a dipalermo, balance and it was a frame supposedly with the help of Costello, for the murder attempt. That's why galante blew the doors off Costello tomb.
The FBN agents were highly feared as well.