A federal appeals court panel has rejected a challenge to special counsel Robert Mueller's appointment in a case involving an associate of Roger Stone.
The three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit released its opinion Tuesday.
The case before the court was brought by Andrew Miller. He is an associate of Stone, a former Trump campaign adviser.
Miller refused to testify before a grand jury in the Russia probe, challenging the legitimacy of Mueller's appointment. A lower court held Miller in contempt.
Miller's attorney, Paul Kamenar, has said the issue of Mueller's appointment is bound to be decided by the Supreme Court.
Stone has pleaded not guilty to lying to Congress, witness tampering and obstruction.