If there's something for Mueller to uncover, then by all means, yes, investigate it. Mueller had better keep it to the Russian Collusion story in my book, though -- and he's found nothing so far. There have been a lot of leaks from Mueller's people to the press, and nothing of note has resulted. The three indictments are unrelated to the issue of Trump/Russia "collusion". Before Mueller was appointed, this particular investigation was commenced from a dossier created by people who were politically motivated to smear Trump. And the smear job occurred both before and after he got elected. Even if the FBI had pure motives to investigate the contents of the dossier at the outset, they don't seem to have come up with anything.
It is fairly apparent that politics have outweighed Justice, and that's been going on since at least the spring of 2016 (in this particular case). So if Mueller has anything then he should come forward, and if he's got nothing, then wrap it up already. The longer this goes with nothing the more Mueller comes across as a hack for political opponents of the President. All you hear from one side of the aisle is "not my president", "resist", "investigate", "impeach", "Muller good", "can't wait until the midterms". It is a really bad narrative. That can't be overstated.