Washington (CNN) A Russian oligarch who was questioned by special counsel Robert Mueller and recently sanctioned by the US visited President Donald Trump's personal attorney Michael Cohen in Trump Tower during the presidential transition in January 2017, according to video reviewed by CNN and a person familiar with the matter.

The January 9, 2017, Trump Tower appearance by Viktor Vekselberg, which was also reported Friday by The New York Times , adds to the questions swirling over the payments to Cohen, which Mueller's team questioned Vekselberg about after the FBI stopped his private jet at a New York-area airport earlier this year.

Vekselberg, chairman of Russian asset manager Renova Group, was accompanied at Trump Tower by Andrew Intrater, who is Vekselberg's cousin and head of Columbus Nova. Vekselberg is Columbus Nova's biggest client.

A person familiar with the meeting told CNN that Vekselberg and Intrater met with Cohen and discussed improving US-Russia relations. The meeting was brief, the person said, and Vekselberg was not originally expected to attend.

An attorney for Cohen did not respond immediately to a request for comment. A representative for Vekselberg also did not respond immediately to a request for comment.

Intrater's firm, Columbus Nova, paid $580,000 to Cohen for a consulting contract starting in January 2017.

Since the payments have become public, Columbus Nova has attempted to distance itself from Vekselberg, denying Vekselberg used Columbus Nova as a conduit to pay Cohen. Columbus Nova recently removed references to Renova Group from the biography of its partners. It has stated it's a "management company solely owned and controlled by Americans," and that it hired Cohen after Trump's inauguration.

But the newly discovered video indicates that Vekselberg and Intrater were meeting with Cohen before that, and they were just steps away from the President-elect during the transition.

Vekselberg was questioned by FBI agents working with Mueller earlier this year about the Columbus Nova payments to Cohen, as well as more than $300,000 in donations made by Intrater to Trump's inauguration and the Republican National Committee, sources said.

Intrater was also questioned, the sources said. Intrater's lawyer, Richard Owens, said, "Columbus Nova has cooperated with all requests for documents and information from federal authorities."

The questions asked of Vekselberg suggest that Mueller's team has been examining some of Cohen's business relationships as part of the investigation into Russian meddling in the 2016 presidential election.

Cohen's home and office were raided last month as part of a criminal investigation by federal prosecutors in Manhattan. In court documents, the prosecutors said at least part of their inquiry stemmed from a referral from Mueller's office.

The US Treasury Department placed Renova Group and Vekselberg on the list of sanctioned individuals and entities last month, for activities including election interference. The sanctions prohibit Vekselberg from traveling to the US.

Arriving at Trump Tower

Video from the lobby of Trump Tower shows that Vekselberg and Intrater arrived on the afternoon of January 9, roughly three hours after Trump had spoken in the lobby with Jack Ma, the head of Chinese firm Alibaba.

The pair -- Vekselberg in a hat and pea coat, Intrater holding a patterned scarf -- checked in at the Trump Tower security desk and lingered for several minutes. They then entered an elevator unaccompanied to head up to Cohen's office in the Trump Organization, according to the person familiar with the meeting.

Twenty-seven minutes later, Vekselberg and Intrater came back down to the lobby and left the building.

Cohen's office was on the 26th floor of Trump Tower, which was the same floor as Trump's office. Vekselberg and Intrater did not meet with Trump while they were at Trump Tower, the person familiar with the meeting said.

The January 2017 meeting joins a list of notable meetings at Trump Tower between members of Trump's inner circle and Russian officials, including the June 2016 Trump Tower meeting between Donald Trump Jr., Trump campaign chairman Paul Manafort, Trump son-in-law Jared Kushner and a Russian lawyer. And in December 2016, Kushner met with then-Russian Ambassador Sergey Kislyak and Russian state banker Sergey Gorkov.

How Cohen got hired

Columbus Nova hired Cohen to raise money from wealthy individuals around the globe, according to sources familiar with the relationship.

Cohen was introduced to Intrater at a New York City restaurant in fall 2016, according to one source. It was through the same acquaintance that Intrater donated $250,000 to Trump's inauguration fund, one source said. Intrater also donated $35,000 to the Trump Victory Fund and $29,600 to the Republican National Committee.

Intrater attended the January 2017 inauguration with Vekselberg. Mueller's team asked Vekselberg about Intrater's payments tied to the inauguration, which was how he was able to attend.

The exact details of who sought out the relationship between Cohen and Intrater is not entirely clear, but Columbus Nova ultimately hired Cohen on a one-year contract that they mutually ended about six months into it when Cohen did not deliver, the source said.

Columbus Nova said after the inauguration it hired Cohen "regarding potential sources of capital and potential investments in real estate and other ventures." The firm raises money for each investment it does, whether it's in real estate or media. The company was seeking to diversify and bring in new investors, the source said.

After six months, Cohen didn't produce any investors and they mutually agreed to end the relationship, the source said. Cohen proposed at least one potential investment in the food and beverage space, according to the source, and Columbus Nova passed on it.

Columbus Nova was one of several companies, including telecommunications company AT&T and pharmaceutical giant Novartis that hired Cohen in the months after Trump won the election. At the time, AT&T was seeking government approval for its acquisition of Time Warner, CNN's parent company.

Cohen, seeking to capitalize on his proximity to the President, pitched companies about a variety of business consulting ideas, including investing in taxi medallions, one source said. Cohen had worked for a decade with the Trump Organization and served as a "fixer" to Trump, but Cohen was left without a role when assignments in the new administration were appointed.

AT&T and Novartis have since called their independent decisions to hire Cohen a "mistake." Both companies said they were contacted by Mueller's office and cooperated.

Update: This story has been updated with additional details about the meeting and Cohen's work with Columbus Nova.