A mystery case stemming from Special Counsel Robert Mueller’s Russia probe has landed before the U.S. Supreme Court, according to CNN. A company owned by a foreign government asked the justices to stay grand jury subpoena it received after a federal appeals court ordered it to comply and turn over information or face a fine. The secret case has been wending its way through the court system for months with few clues emerging. If the Supreme Court decides to hear arguments it could be the first time all nine justices would hear a sealed case, CNN said. “There’s no procedure in the court’s rules for having the whole case briefed, argued and decided under seal,” said Steve Vladeck, a professor at the University of Texas School of Law.