3. Devecchio has been supported by every single one of his superiors in the NYC office at the time. Kollstrum and others have consistently stated publicly the claims were not substantiated. These are honest cops, and if there was a shred of truth, they would have gone after Devecchio with the same vigor they went after LCN.
I don't know, but I think they supported him just because he was "one of them", no matter if dirty or not, and they didn't want to bring bad publicity to the FBI. I doubt they cared about "bringing to justice a dirty one".
It's like that quote from the TV series "Murder One 2":
Never rat on a fellow cop (FBI agent in this case).