Does he have the authority to grant immunity?
Quote from a recent article:
"Special counsel Robert Mueller is asking a judge to grant immunity from prosecution for five potential witnesses at the upcoming federal criminal trial of former Trump campaign chief Paul Manafort, according to a court filing Tuesday.
Mueller has also asked U.S. District Court Judge T.S. Ellis to seal the court motions detailing the witnesses, filings show.
Manafort's trial is due to start on July 25 in federal court in Alexandria, Virginia, where he is currently being held in jail. His $10 million bond was revoked last month after Mueller accused him of trying to tamper with potential witnesses at his trials."