I think the time has come for the DOJ heads, and for Trump himself to ask Mueller about what his investigations have been really about, since, the whole thing was based on a phony dossier, fabricated by the Hillary campaign and the DNC and the Obama administration.
Trump should be asking Mueller about what he (Trump) is being investigated about, and if the answer is about Russian collusion, Trump should throw it right back at him and demand to know there could be collusion allegations from a phony dossier. Mueller cannot have a good answer to that at all. If Mueller mentions obstruction into the investigations, Trump can answer with the same reply, where there cannot be obstruction of investigations based on a phony set of allegations from a phony dossier.
Mueller is trapped. He cannot, in any shape, way or fashion, come up with anything against Trump based on a phony dossier. Mueller is also trapped on the opposite side of the investigations, where he had better turn up indisputable cases of attempted sedition on the part of the people who fabricated the phony dossier. He has to turn up with charges, but against those who planted the phony evidence in the first place. Anything less, will just point to collusion on the part of Mueller himself.
Mueller needs to be perp walked for being an integral part of the RICO conspiracy of Sedition of at least the Three musketeer Weasels (Comey, RosenWeasel and Mueller).