WASHINGTON (Reuters) - Former Trump campaign aide Sam Nunberg emerged from a Washington, D.C., federal courthouse on Friday after spending some six hours before a grand jury convened by Special Counsel Robert Mueller as part of his investigation into whether Russia meddled in the 2016 U.S. presidential election.

Nunberg had defiantly balked at testifying in the investigation that is also looking into whether the Trump campaign colluded with Russia. Neither he nor his attorney made public remarks.

Nunberg, who was subpoenaed by the federal grand jury, spent Monday creating a media frenzy by telling multiple news outlets that he would ignore the order, even at the risk of jail. He speculated on targets of the Russia investigation and said he did not want to sort through an abundance of email despite the subpoena.

A CNN interviewer told Nunberg that she smelled alcohol on his breath but he denied that he had been drinking.

By late Monday, he said he would comply with the subpoena.

On Tuesday, Fox Business Network reported that Nunberg intended to seek treatment for alcoholism following his grand jury appearance.

Nunberg, 36, is an associate of Trump ally and longtime political consultant Roger Stone. Mueller wants to determine if Stone played any role in the publication of Democratic emails hacked by Russian intelligence operatives, according to sources familiar with the investigation.

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Russia has denied that it meddled in the election and Trump has said there was no collusion between Moscow and his campaign.

Nunberg first worked for one of Trump’s businesses and later helped advise his presidential campaign, but he was fired in August 2015 amid reports that he had posted racially charged messages on Facebook.

Nunberg also was close to former White House adviser Steve Bannon, who met with Mueller’s team on several occasions last month, the sources said.

Nunberg was accompanied by his attorney, Patrick Brackley. Lawyers are generally not allowed in grand jury testimony but witnesses can step outside to confer with them.