WASHINGTON (Reuters) - Comedian Randy Credico testified in the trial of President Donald Trump’s adviser Roger Stone on Thursday where he told jokes, did a Bernie Sanders impression and said he never served as a backchannel between Stone and Wikileaks founder Julian Assange.

Roger Stone, former campaign adviser to U.S. President Donald Trump, arrives for his criminal trial on charges of lying to Congress, obstructing justice and witness tampering at U.S. District Court in Washington, U.S., November 6, 2019. REUTERS/ Tom Brenner

Credico is a key witness in the government’s case against Stone, who is charged with obstructing justice, witness tampering and lying to the House of Representatives intelligence committee in its investigation into Russia interference in the 2016 election.

The government alleges that Stone misled the committee in September 2017 by claiming, among other things, that Credico was his intermediary to Wikileaks as Stone sought to learn when Assange planned to dump more damaging emails about Trump’s election rival Hillary Clinton.

In testimony Thursday morning, former FBI agent Michelle Taylor read threatening text messages that Stone had sent Credico in which he urged him not to testify or cooperate in the government’s investigations.

“Prepare to die ...” Stone wrote in one text to Credico that included an obscenity.

The evidence presented also showed that Stone urged Credico on multiple occasions to invoke his constitutional right not to testify and made references to Frank Pentangeli - a character in the film “The Godfather Part II” who recants his testimony to Congress about mobster Michael Corleone amid witness intimidation.

Through texts, Credico later confronted Stone about his lies to the committee and urged him to amend his testimony. He said Stone lied about his being a back channel and had made it appear Credico provided information about Wikileaks in July 2016, when he did not try to make contact with Wikileaks until August 2016 in an effort to arrange a radio interview.

The trial took on a light-hearted tone, however, after Taylor concluded her testimony and Credico took the stand Thursday afternoon.

When the prosecution started to ask Credico to tell the jury about movie characters and public figures he imitates, Judge Amy Berman Jackson said she had been expecting him to “treat us” to an example.

Mistaking it for an invitation, Credico offered to let the jury hear one and managed to squeeze in a quick impression of Democratic presidential candidates Bernie Sanders despite Jackson’s instruction not to do so.

“Then I won’t do it then,” he said, imitating the politician’s accent and shrug to laughter.

Credico said he never had any inside information about when Wikileaks might release emails nor did he discuss the topic with Stone prior to August 2016 as Stone testified.

Credico testified he promised to help get Assange to appear on Stone’s radio show and pass along messages, but he never followed through.

And though he told Stone there was some “big stuff” coming from Wikileaks, he acknowledged on Thursday that those comments were merely made out of “instinct or I was bluffing.”

The government has yet to finish questioning Credico about when his friendship with Stone deteriorated and the alleged threats began.

However, prosecutor Aaron Zelinsky did try to beat back a claim that Stone’s defense attorney, Bruce Rogow, made on Wednesday, when he passed off Stone’s reference to Pentangeli as a joke about Credico’s impressions of the character.

Credico said an impression of Pentangeli was not in his public repertoire. “I did (Al) Pacino and I did Marlon Brando, but I never did Frank Pentangeli,” he said.

The government will continue questioning Credico on Friday morning. The judge instructed the jury not to go home and download “The Godfather.”