Mueller grand jury witness asks court for rehearing

A grand jury witness in special counsel Robert Mueller's investigation is asking a federal appeals court to determine whether he still needs to testify now that the Russia probe has concluded.

Andrew Miller, a former aide to Trump confidante Roger Stone, made the request Friday in a petition before the U.S. Court of Appeals for the District of Columbia three weeks after Mueller turned in his final report. The filing could help shed light on the continued use of a grand jury that brought lying and obstruction charges against Stone and was previously used by Mueller.

Last year, Mueller's team sought Miller's testimony regarding Stone, WikiLeaks and the Russian government-controlled online persona Guccifer 2.0, which was used to release hacked material during the 2016 election. But Miller challenged his grand jury subpoena, arguing that Mueller's appointment was unconstitutional.

Earlier this year a three-judge panel of the court upheld the special counsel's appointment and a contempt order intended to force Miller to testify.

In the new petition, Miller's attorney, Paul Kamenar, argued that the matter now appears to be moot because Stone has been indicted and like "Cinderella's carriage that turned into a pumpkin at midnight, special counsel Mueller's authority expired."