Former Trump aide speaks to Mueller, believes Russia probe is 'not a witch hunt' “I don't believe it leads to the president," former aide Sam Nunberg said.

Five and a half hours after testifying before a grand jury in the Russia probe, a former political adviser to Donald Trump told ABC News exclusively that he believes the investigation is “warranted.”

“No, I don't think it's a witch hunt,” Sam Nunberg told ABC News. “It's warranted because there's a lot there and that's the sad truth.”

He added, “I don't believe it leads to the president.”

Instead, Nunberg said he believes that many in his inner circle may face legal trouble, including his own mentor and former Trump campaign aide, Roger Stone.

“I'm very worried about him,” Nunberg said. “He's certainly at least the subject of this investigation, in the very least he's a subject.”

Stone has testified before congressional investigators in the Russia probe, and told ABC News that he would expect Mueller’s team to ask him for documents or emails. But, he said, he had “no knowledge or involvement in Russian collusion or any other inappropriate act.”

On Monday, Nunberg made headlines for announcing his intention to defy the special counsel’s subpoena in a series of cable news and newspaper interviews.

"Let him arrest me," Nunberg told the Washington Post, referring to the special counsel, Robert Mueller. "Mr. Mueller should understand I am not going in on Friday."

But he told ABC News this was all “for show.”

“They said it was a media meltdown. I felt I melted down the media,” Nunberg said in an interview with ABC News on Friday. “I felt it was a good game… And if you want to know the truth it’s kind of therapeutic too.”

He did admit that the performance was partially due to the pressure of testifying in the special counsel’s probe.

“I wanted to show what this independent counsel, this independent investigation does to people like me,” Nunberg said. “I'm collateral damage in this independent special investigation.”

By Friday, however, Nunberg had changed course and ultimately cooperated with Mueller’s subpoena, testifying for more than five hours before a federal grand jury in Washington, D.C.

Nunberg said he was always going to comply with the law and added, “I’m an attorney”.

It's unclear what exactly Nunberg testified about before the grand jury. He declined to publicly elaborate on what prosecutors wanted to know, saying he “got into enough trouble this week” already.

Nunberg said his testimony focused on the campaign aides surrounding the president who were mentioned in the subpoena, like White House Communications Director Hope Hicks, former White House aide Steve Bannon, former campaign aides Corey Lewandowski and Carter Page, Trump's personal attorney Michael Cohen, and the president's longtime bodyguard Keith Schiller.

He said there were also questions about Trump’s business and his political positions on Russia.

Nunberg described the atmosphere inside the grand jury room as “professional” and noted the pace at which he said prosecutors fired questions at him.

“They’re trying to get as much in as quickly as they can – boom, boom, boom, boom – it almost feels like I’m back in yeshiva with the rabbi.”

Nunberg’s tenure with Trump is checkered.

Having served as a political adviser to then-businessman Trump beginning in 2011, Nunberg was fired by Trump in August 2015 after multiple racially-charged comments were discovered on his personal Facebook account.

In 2016, Trump sued him for $10 million, accusing Nunberg of violating a nondisclosure agreement and leaking confidential campaign information to the press. Nunberg denied the allegation and the suit was ultimately settled for an undisclosed amount.

Nunberg declined to say whether he’d be back in front of the special counsel’s attorneys or the grand jury. A source close to him said he is scheduled to testify five more times.

“Look I can't talk. I can't. I'm just not going to talk about it. Maybe, maybe yes, maybe no, I'll give you a Donald Trump answer,” he said. “We'll see.”