Trump business associate to be interviewed by Senate committee investigating Russia election meddling Felix Sater arrived on Capitol Hill Wednesday for an interview with the Senate.

Donald Trump's longtime business associate Felix Sater arrived on Capitol Hill Wednesday for a closed door interview with the Senate Intelligence Committee investigating Russian election interference.

He did not comment on the appearance to reporters on the way to his interview with Senate investigators.

The Russian-born businessman was once involved in a proposed plan to build a “Trump Tower Moscow” during the 2016 presidential campaign, along with Trump attorney Michael Cohen, a childhood friend.

“I know how to play it, and we will get this done,” Sater wrote to Cohen in emails first published by The Washington Post and The New York Times. “Buddy, our boy can become president of the USA, and we can engineer it.”

Sater, a convicted felon and one-time stock scammer, also once vowed to “get all of Putin's team to buy in” on a proposal to build “Trump Tower Moscow” in the heat of the presidential campaign.

That project was scrapped. However, Sater became a focus as the special counsel’s probe broadened to include possible connections to Trump’s campaign and personal businesses.

Sater, 52, says that for the past two decades he has served as a high-level intelligence asset for the DIA, CIA and the FBI. As Buzzfeed News first reported, Sater helped bust mafia families, assisted in the capture cybercriminals and the pursuit of top terrorists — including Osama bin Laden — efforts which helped him net praise from some of the country’s top law enforcement officials.

Sater will not say whether or not he’s been interviewed by Mueller. However, the special counsel may be familiar with his efforts since he was FBI Director during much of Sater’s clandestine career.

Sater, in an interview with ABC News’ George Stephanopoulos in March, sought to recast himself as an unsung and patriotic protector.

“I am a patriot,” Sater said. “Having the opportunity to serve my country and do anything in its defense was a no-brainer. It was, ‘Where do I sign up?’”

ABC News' Pete Madden and Meghan Keneally contributed.