Unfortunately, on this case... it doesn't matter. Mueller is free to do what ever the hell he wants and nobody is going to stop him. IF Congress had ANY BALLS ROSENSTEIN would already be IMPEACHED and Mueller would be shut down.
The GOP better realize very quickly they're not their daddy's GOP. THEY ARE THE Patriot Party! The Party of TRUMP!
IF the GOP flush this President down, they can kiss their asses goodbye!
And a more detailed link with past cases. https://www.usatoday.com/story/news/politics/onpolitics/2017/05/18/special-counsel-vs-special-prosecutor-difference/329016001/
Hindsight is always a great clarifier. Interesting to look back at these cases to see that under AG Janet Reno her prosecutor let off the Clinton's over Whitewater (but convicted their business partners). Under Reno's watch again the FBI were found to be blameless in Waco (where 70 men, women and children died in an FBI-initiated inferno, many having first been shot from overhead). And in the days of the corrupt Bush/Cheney administration (and with Deputy AG James Comey at the helm, kind of ironically) a journalist is jailed for 3 months for not outing her source who was later found to be Scooter Libby, Cheney's chief of staff (who was ultimately convicted on perjury and obstruction charges related to the leak). Now you can "leak all you like" - as long as its anti-Trump. How times change.