London and Moscow(CNN) Senate investigators want to question a Moscow-based American businessman with longstanding ties to President Donald Trump after witnesses told them he could shed light on the President's commercial and personal activities in Russia dating back to the 1990s, multiple sources have told CNN.

The Senate Intelligence Committee, which is probing allegations of Russian interference in the 2016 elections, has been keen to speak with David Geovanis for several months, the sources say.

Geovanis helped organize a 1996 trip to Moscow by Trump, who was in the early stages of pursuing what would become a long-held goal of building a Trump Tower in the Russian capital, according to multiple media reports at the time.

Years later, Geovanis worked for the Russian oligarch Oleg Deripaska, whose ties to Trump's 2016 campaign chairman Paul Manafort have also been of interest to investigators.

Moscow-based businessman David Geovanis

Two witnesses who have given evidence to the Senate Intelligence Committee say they were asked about Geovanis' past relationship with the President during interviews last year. The interviews were conducted by staff working for both the Republican and Democratic sides of the committee, according to the sources, who wish to remain anonymous due to the confidential nature of the Senate inquiry.

This is the first time that Geovanis' name has been revealed in connection with the various investigations underway into Russian influence on US politics, which include a sweeping new House investigation into Trump's financial interests.

The Senate Intelligence Committee's interest in Geovanis indicates its investigation is delving further back into Trump's past in Russia than previously thought.

A businessman, three women and Joseph Stalin

One of the two witnesses says the committee has a photograph of a younger Geovanis apparently posing in a portrait with three partially clothed women. The portrait, once displayed in a Russian gallery under the title "The Capitalist," depicts the subjects in front of a picture of the former Soviet leader Joseph Stalin. It's not clear whether the portrait is a single photograph or a composite.

The witness told CNN that they were shown the photograph during questioning.

David Geovanis in a portrait with three unnamed women and a picture of Stalin. CNN has blurred the women's faces to protect their identity.

A third witness has alleged in written testimony, seen by CNN, that Geovanis may be valuable in the mystery of whether Russia has material on Trump that could be personally embarrassing to him.

Known by the nickname "Geo" to his friends, Geovanis was born in Brockton, Massachusetts, and is a graduate of Trump's alma mater, the Wharton School at the University of Pennsylvania. After starting his career in finance, Geovanis went to Moscow to work for a Russian venture of a company called Brooke Group, which owned land earmarked for the site of a proposed Trump Tower. When Trump came to town to promote the project, sources say, it was Geovanis' job to show him around.

Also on the trip were Brooke Group's owners, the real estate moguls Bennett LeBow and Howard Lorber, who went on to become substantial donors to Trump's 2016 presidential campaign. Trump personally acknowledged the pair from the podium after he won the 2016 New York Republican primary.

An archive video report of Trump's 1996 Moscow trip emerged online in late January. The news report -- misidentified on YouTube as dating from 1995 -- shows Lorber, Lebow and Trump in discussion with Moscow's then deputy mayor, Vladimir Resin, and his staff, with Geovanis looking on from the background.

Blocked numbers and 'dirt' on Clinton

Lorber has already been linked to the Senate investigation into Russian meddling in the 2016 elections. The New York Times named him earlier this month as one of the Trump family associates who spoke with Donald Trump Jr. from blocked numbers around the time of a highly scrutinized 2016 meeting at Trump Tower in New York.

That meeting was attended by top Trump campaign advisers --- Trump Jr., the President's son-in-law Jared Kushner, and Manafort -- and Russian lawyer Natalia Veselnitskya, who had promised dirt on Trump's election opponent, Hillary Clinton. Lorber has not responded to multiple calls for comment.

Donald Trump (seated, center) on his 1996 visit to Moscow. To his right are real estate moguls Bennett LeBow and Howard Lorber.

When contacted by CNN via telephone, Geovanis declined to comment on his relationship with the President or talk about the photograph said to be in the possession of the Senate Intelligence Committee. He would not disclose his location, although CNN was able to confirm he was in the Moscow area as recently as this month. Asked whether he had been approached by the committee and whether he was aware of its interest, Geovanis told CNN he had "no comment."

A spokeswoman for the Senate Intelligence Committee's Republican chairman, North Carolina Sen. Richard Burr, declined to comment on whether Geovanis was of interest to it. A spokeswoman for the committee's Democratic Vice Chair, Virginia Sen. Mark Warner, also declined to comment.

It's not known whether Geovanis is also of interest to the investigation into alleged Russian election meddling by special counsel Robert Mueller.

The President's legal team declined to comment on his relationship to Geovanis. A lawyer for the Trump Organization also declined to comment.

A tower that never got built

Geovanis was quoted by the Moscow Times in 1996 as saying officials were "very receptive" to the original Trump Tower project, but Trump's early designs on the Moscow skyline never got off the ground.

Discussions two decades later to build another Trump Tower in the Russian capital have been a focal point in the Mueller investigation.

Trump has often denied that his dealings with Russia continued into the 2016 campaign. Even in late 2018 Trump tweeted he "never met a single Russian official."

Trump (left) is accompanied in Moscow by the real estate mogul Bennett LeBow (second from left).

It is not clear what prompted the Senate Intelligence Committee's interest in Geovanis. But multiple sources familiar with its activities tell CNN their inquiries date back to spring last year when it sent him a letter requesting he give evidence. The sources say he has not yet done so but added that he had appointed US legal counsel.

Lebow and Lorber changed their company name from Brooke Group to Vector Group, a Nasdaq-listed cigarette and real estate company. Vector Group's top three shareholders include Renaissance Technologies, the hedge fund once run by Robert Mercer, the conservative donor who was once a patron of business and political ventures of Steve Bannon, Trump's former chief strategist.

A spokeswoman for Vector did not reply to CNN's emails requesting comment. A fax to BSL Capital, Lebow's family firm, went unanswered, despite an assistant confirming it had been received.

Geovanis, who married a Russian woman, obtained a Russian passport in 2014. He was last seen by family members in the US in early 2017 after the death of his mother.

He is not believed to have returned to the US since then, and his decision to remain in Moscow means US congressional investigators can't easily find out what he knows.

In 2017 Geovanis was reemployed by Lebow to set up the Russian arm of another venture, Somerset Coal International, an energy technology company which claims to "clean" coal by washing it at high pressure.

Among those approached by Geovanis for investment was Deripaska, the billionaire metals and mining magnate, for whom Geovanis worked in the mid-2000s, according to a person familiar with Somerset Coal's business plan, speaking on condition of anonymity.

Deripaska is so closely aligned with Russian President Vladimir Putin that the US sanctioned him and his companies in order to punish the Russian government for its activities around the 2016 election. The Trump administration lifted sanctions on three of those companies last month.

A spokesperson for Deripaska did not return CNN's requests for comment.