A former associate of ex-Trump adviser Roger Stone is challenging the validity and power of Special Counsel Robert Mueller, Trace Gallagher reported.

Andrew Miller, who served as a scheduler for Stone in 2016, was subpoenaed by the Mueller team to appear before a grand jury and testify on matters related to WikiLeaks and other topics, Gallagher said.

Miller was charged with contempt, a charge his attorney invited because it allowed for Miller to challenge the legitimacy of Mueller's probe, he reported.

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Attorney Paul Kamenar told Melissa Francis on "The Story" that he was interviewed by the FBI in May and turned over documents but turned down a subpoena for a June court date.

Kamenar challenged that Mueller's appointment does not fall in line with any statute, since such appointments must be made by the attorney general. Deputy Attorney General Rod Rosenstein appointed Mueller.

As the Associated Press reported:

Kamenar... argued after the proceedings that Mueller’s appointment is unconstitutional. He asserted that Deputy Attorney General Rod Rosenstein did not have the authority to appoint Mueller to lead the investigation into Trump campaign contacts with Russia.

Previous challenges to Mueller’s legitimacy have failed.

President Donald Trump has sought to undermine the investigation by calling it a “witch hunt” and a “hoax.” He has repeatedly insisted, “there was no collusion.”

Kamenar also said a prosecutor with powers as broad as Mueller’s should be treated like a U.S. attorney and be subject to Senate confirmation.

“There’s been no authority, we say, that gives the Justice Department the power to appoint Mr. Mueller,” Kamenar told reporters outside the courthouse in Washington after Miller was held in contempt for refusing to appear before the grand jury.

Miller and Kamenar also contend that Mueller did not go through a Senate confirmation, which they say violates the Constitution, Francis reported.

Kamenar said the case is likely to end up before the Supreme Court and displays "serious constitutional issues" as to "whether Mueller was properly appointed."

Watch more above.

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