Special counsel Robert Mueller issued a subpoena on Thursday for another former aide to longtime Trump adviser Roger Stone.

Andrew Miller, a media liaison for Stone during the 2016 presidential election, must appear before a grand jury and turn over documents to the Office of the Special Counsel. An attorney for the former Stone aide said he will fight to have the subpoena quashed.

“A lawyer, Paul Kamenar, said he planned to file a motion on Thursday on behalf of a client who was subpoenaed to be questioned in front of the grand jury, though he did not identify Mr. Miller. Mr. Kamenar said the National Legal and Policy Center, a conservative nonprofit organization, was paying for his services,” reports the New York Times.

John Kakanis, a body man for Stone, along with social media specialist Jason Sullivan, were subpoenaed by Mueller in the spring.

The FBI questioned Kakanis over Stone’s communications with Gufficer 2.0 and WikiLeaks founder Julian Assange during the 2016 election.

Sullivan, who previously functioned as Stone’s “Chief Social Media Strategist,” was ordered to appear before a grand jury on May 18 at a Federal D.C. Court.

Stone in May told Chuck Todd of NBC’s “Meet the Press,” that he is prepared to be indicted by Mueller.

“I can guarantee you they have found no evidence whatsoever of Russian collusion, nor trafficking of allegedly hacked emails with WikiLeaks,” Stone began. “It is not inconceivable now that Mr. Mueller and his team may seek to conjure up some extraneous crime pertaining to my business, or maybe not even pertaining to the 2016 election.”

“But I think it just demonstrates, again, this was supposed to be about Russian collusion, and it appears to be an effort to silence or punish the president’s supporters and his advocates,” he added.

Last fall, Stone told House Intelligence Committee members he had no knowledge of collusion between Trump campaign officials and Russia.

“I am aware of no evidence whatsoever of collusion by the Russian state or anyone in the Trump campaign,” he said.