I crossed paths with Jimmy Mulligan and Anne Burgess briefly in the mid '80's a little while after they were "Out" of the GO. In the interests of my anonymity I'm not going to discuss the circumstances or whereabouts, although I will say it was not where they were living. I have not been in contact with them since and have no clue where they are today, where their "heads" are at or if they are still together.
I ipersonally nteracted with both Jimmy and Anne a few times during my SO career. I think the idea that Mulligan was a government "Plant", "Stooge", "Operative" or whatever is bogus. The US Gubmint may well have surveilled Scn then and attempted infiltration...I dunno...your guess is as good as mine. I, personally, very seriously doubt that Jimmy, or Anne, were GMen that penetrated the Inner Circle. Getting invited and allowed in and surviving there for even a short period of time was not easy, would be complex to set up the "stage" for and rest heavily on a matter of random luck. Even if an FBI Spook managed to navigate all that, due to the compartmentalization, many posts were surprisingly "in the dark' about all of what was going on and would have to depend on the "Skinny Line" for any valuable meat and potatoes.
Now, I guess someone could try to make the "Case" that Jimmy "turned" or was "turned" but, based upon my interaction with him pre and post his USGO tenure and the lack of any actual evidence or credible narratives I don't buy that one iota. If Mulligan had "turned" or was an "inside man" for the Gubmint the FBI and the IRS woulda had everything they needed to do a successful "Capone Case" on El Ron, well before Hisself departed to do Upper Level Research without the emcumbrance of humanoid flesh.
That's my take on it FWIW and, quoting Forrest Gump, "That's all I have to say 'bout that."