And while Mueller also tried to set up a "perjury / obstruction" trap for Trump and his supporters, Mueller and his crew got caught in Trump's "give them enough rope to hang themselves" trap. They committed crimes investigating Russian collusion (for example they faked interview transcripts with General Flynn) which are now coming out.
The New York Times reported:
Attorney General William P. Barr has assigned an outside prosecutor to scrutinize the criminal case against President Trump’s former national security adviser Michael T. Flynn, according to people familiar with the matter.
Mr. Barr has also installed a handful of outside prosecutors to broadly review the handling of other politically sensitive national-security cases in the U.S. attorney’s office in Washington, the people said. The team includes at least one prosecutor from the office of the United States attorney in St. Louis, Jeff Jensen, who is handling the Flynn matter, as well as prosecutors from the office of the deputy attorney general, Jeffrey A. Rosen.
I can't tell if this means they are investigating crimes by FBI, the Mueller investigation, and other DOJ officials or if they are just looking to remedy any possible unfair treatment of defendants.