The one investigation that is basically needed is an investigation into the FBI activities of Mueller during H. Clinton´s term as Sec. State and up to the firing of Comey. Until he is cleared of any collusion with Obama-Clinton-Comey FBI subterfuge, he should be placed on leave, with pay, from USGov service. The findings of such an investigation would determine further action regarding Mueller.
He should be immediately declared to be disqualified from investigating Donald Trump, or ANYONE.
Wind: 4 mph