When they really, really want to know what is going on, they send in this agent:
I was thinking more of Barney Fife...
I've seen "Special Needs Elders" come in to congregations to "clean" them up. Usually it was when there was some serious problems within the congregation or elder body. Usually there was some major wrongdoing and coverup. Of the cases that I've seen the congregations were happy when the new elders came in and cleaned house.
I don't remember them weeding out apostates or dissidents as much as they were trying to make sure the KH was run by Society standards (in their words: "keeping the congregation clean and above reproach". I bet a "Special Needs" group has never been sent to KHs with child abuse issues).