Well, maybe he intends something entirely different.
I don't know about you, but I would love the chance to brief this group, and I would love it even more if I were the FBI Director. At the conclusion, they would have no doubt as to what to expect from us and no doubt about what was expected of them. I imagine Mueller has something similar in mind.
And M2C, I don't know about UBL in particular, but if you want more info about these folks and who they support, do a search for "American Museum Council" (sic) and Hillary Clinton.