Roger Stone, a Republican operative and former adviser to President Trump, tried to secure a pardon for WikiLeaks founder Julian Assange earlier this year, telling an associate not to “fuck it up.”

“I am working to get JA a blanket pardon,” Stone wrote in a January text message to Randy Credico, a comedian who Stone has identified as his backchannel to WikiLeaks during the 2016 presidential campaign.

“It’s very real and very possible. Don’t fuck it up,” Stone continued.

Later he added, “Something very big about to go down.”

The messages were obtained by Mother Jones, which reported Thursday that special counsel Robert Mueller’s team is investigating Stone’s push for a pardon. Stone, who has not been publicly charged with a crime in the Russia investigation, confirmed the pardon effort to the Washington Examiner.

“I never communicated directly to the President but did mail him my DAILY CALLER piece and I did urge my friend Andrew Napolitano to write to him,” Stone said in an email to the Washington Examiner.

Credico, who denies being Stone’s backchannel to WikiLeaks, said Stone repeatedly discussed an effort to secure a pardon and claimed that he had been working with Napolitano, a Fox News personality, on a plan in which Napolitano would suggest the idea on his show or directly to Trump.

Napolitano denied working with Stone to win a pardon for Assange.

Sam Nunberg, a former Trump campaign aide, told Mother Jones that prosecutors have asked him if Stone “ever discussed pardons and Assange.” Nunberg said he had not heard Stone bring up the topic.

Stone floated the idea in an August interview with the Washington Examiner. Stone said then that he had not spoken with Trump about pardoning Assange.