I do not see that Trump or Sessions can fire Mueller. Sessions and Rosenstein should direct Mueller to close down the discredited investigation and issue final report in 30 days. In its place, Sessions should appoint a new special counsel to investigate DOJ/FBI collusion to undermine the election and involve itself in politics, causing discredit to the DOJ/FBI.
“I do not see that Trump or Sessions can fire Mueller. “
Absolutely he can. Trump is the head of the Justice Department. Sessions is merely the Secretary.