RR and Mueller are doing what they have always been expected to do by the Democrats.
In other words - the mafia expects the dirty cops to be playing on their side. Are they, though? RR offered up a resignation rather early in the game if he expected to be protected by the democrats and if he was playing to try and force POTUS into firing him to trip the 'obstruction' narrative.
Mueller has likely been referring cases to that new Marine Cyber intelligence unit as he comes across them with the angry democrats (who are probably angry because they are desperate to find collusion before they are sent to gitmo).
I would argue that Mueller and RR are dirty cops who have played for the mafia long enough to be trusted by the mafia… And now they have turned to be our dirty cops… And that was probably part of the plan all along (decades).