The House Intelligence Committee is investigating Russian meddling in the U.S. election -- and whether anyone in the Trump campaign was involved. On Friday, former Trump campaign adviser Michael Caputo testified to the panel in closed session.

"I had no contact with Russians and I never heard of anyone in the Trump campaign talking with Russians," said Caputo, who met with House investigators for nearly four hours on Friday. He said he testified that he had zero contacts with Russians during his time on the campaign.

Caputo, who was on the Trump campaign from November 2015 to June 2016, had lived in Russia in the 1990s while working for the U.S. government.

He returned to the U.S. in 2000 and worked as a public relations adviser to a subsidiary of the state-owned Russian conglomerate, Gazprom. Last year he told the Buffalo News, "I'm not proud of the work today, but at the time, [Russian President Vladimir] Putin wasn't such a bad guy."

Former Trump campaign adviser Michael Caputo speaks after testifiying before the House Intelligence Committee. CBS News

"I have intentionally stayed out of the hair of the White House and the administration, especially since my name was brought up in the context of the Russian investigation," Caputo said Friday. "Nobody in the administration or the White House needs my telephone on their call list, needs me on their visitor logs or needs emails from me."

He's a protégé of one of Mr. Trump's longest advisers, Roger Stone, whose appearance before the House committee later this month was postponed so members have more time to prepare.

For his part, Stone says he's had no contact with Russian officials. But he told CBS News' Jeff Pegues he was in touch with Russian hacker Guccifer 2.0 and WikiLeaks during the campaign. One of his tweets last year suggested he may have known the site would be posting Clinton campaign chairman John Podesta's hacked emails.

Also on Friday, Brad Parscale, the Trump campaign's data and digital director, tweeted he'll speak with House investigators. He said he's "unaware of any Russian involvement" and will share with the committee "everything I know."

My statement on the House Intelligence Committee's request to interview me about the 2016 election. pic.twitter.com/Aamz6gQFGS — Brad Parscale (@parscale) July 14, 2017

Mr. Trump's longtime attorney, Michael Cohen, is also scheduled to appear before the committee in September. Both the House and Senate are still in the early stages of their investigations, which will eventually move up the ladder to the president's inner circle.