Jerome Corsi, an associate of former Trump adviser Roger Stone, is in plea negotiations with special counsel Robert Mueller, he confirmed to The Associated Press on Friday.

Corsi, a conspiracy theorist and conservative writer, has close ties to Stone and President Trump. He provided opposition research about Democrats to Stone, an informal Trump adviser, during the 2016 presidential campaign.

The plea negotiations were first reported by The Washington Post.

The plea deal negotiations are another indication that Mueller's investigation into ties between Russia and the Trump campaign is homing in on Stone. The special counsel has reportedly been probing how much Stone knew about the release of emails hacked by Russians and released by WikiLeaks in 2016.

Corsi said earlier this month that he believed Mueller would indict him for giving false information to federal investigators despite cooperating with the Russia investigation.

The special counsel has been scrutinizing whether Corsi was aware that WikiLeaks had obtained Democratic emails hacked by Russian intelligence officers and whether he may have shared information about the email release with Stone, a longtime friend of Trump.

The deal Corsi is discussing with Mueller's team could result in him pleading guilty in exchange for leniency, the Post reported. It is so far unclear what information he could offer Mueller.

Corsi said earlier in November that he predicted that WikiLeaks would release the hacked emails because he "figured it out," and not because of any contact he had with founder Julian Assange.

Stone has denied having any improper ties with WikiLeaks or feeding information to the Trump campaign ahead of the release of the emails.

Stone said in an email to The Hill that his attorneys have seen all of his communications with Corsi and that they "prove everything I have said under oath regarding my interaction with Dr. Corsi is true."

"I stand by my statement to the House Intelligence Committee and can prove it is truthful if need be," Stone said. "I have passed two polygraph tests administered and analyzed by two of the nations leading experts to prove I have truthful."

Corsi has said that he has been cooperating with the special counsel for months.