Anyone who has followed the story of Trump and Russia knows the name of Carter Page, the bullet-headed Trump campaign advisor who became the subject of a top-secret investigation into whether he was or was not a Russian agent.

Less well-known, in fact hardly known at all, is Page’s 59-year-old business associate, Sergey Yatsenko.

In his testimony before the House intelligence committee, Page described Yatsenko as an “old friend” and “an international advisory board member” of his New York-based firm, Global Energy Capital LLC. The Mueller report describes Yatsenko as a “senior advisor” working with Page on a contingency basis.

An examination of Yatsenko’s background reveals more: a wealthy, well-connected man with a past that suggests — but doesn’t prove — connections in Russian intelligence circles. Page didn’t respond to a message left seeking comment; Yatsenko could not be reached.

Page and Yatsenko met while Page was the deputy branch manager of Merrill Lynch’s office in Moscow from 2004-2007. At the time, Page was working on large deals involving the Russian gas giant, Gazprom, “such as buying of a stake in the Sakhalin oil and gas field in the Sea of Okhotsk,” Bloomberg reported.

(Interestingly, Page’s boss at Merrill’s Moscow office, Allen Vine, left in 2006 to work for Suleiman Kerimov, a Kremlin-connected tycoon and member of the upper house of Russia’s parliament who has been sanctioned by the U.S. Treasury.)

When he met Page, Yatsenko was then Gazprom’s deputy chief financial officer. He worked on large deals involving the takeover of Roman Abramovich’s oil giant Sibneft as well as a $200 million loan from Deutsche Bank.

Most interesting to me was Yatsenko’s position on the board of Gazprombank from 2008-2009. Gazprombank has backed projects by Dmitry Firtash, a Ukrainian billionaire, who was indicted in Chicago for bribery. Prosecutors have called Firtash an “upper echelon” associate of Russian organized crime. (Despite its name, Gazprom only holds a minority stake in Gazprombank.)

After leaving Gazprom in 2010, Yatsenko joined forces with Page and relocated to London. He also acquired a small fortune in European real estate.

A £3 million flat in fashionable Chelsea and a £6.2 million six-bedroom home in Kensington are held in the name of Yatsenko’s wife, a banker based in London who specialized in Russian energy deals.

According to sources, Yatsenko’s wife also holds property in the south of France, via a real estate investment company. The property is worth an estimated 3 million Euros.

Russian corporate records show Yatsenko holds a stake in the Severyanin (Northerner) Homeowners Association 31, a corporate town was built in 2006 for top Gazprom employees. Another co-owner is Mikhail Putin, a second cousin of the president, who had worked in Gazprom’s medical department.

Page, by contrast, is a man of limited resources. The Mueller report notes that he was forced to draw down his life savings to support himself and pursue his business. Page represented himself in his now-dismissed lawsuits against the Democratic National Committee and Yahoo! parent Oath Inc. He told the House intelligence committee that, in 2016-17, he was living off passive investments.

The mystery then is what drew Yatsenko into business with a nobody, a man few in the Russian energy sector had ever heard of before he joined the Trump campaign. “I can poll any number of people involved in energy in Russia about Carter Page and they’ll say, You mean Jimmy Carter?’” one veteran Western investor in Russian energy told Politco’s Julia Ioffe.

Could their relationship have something to do with the fact Page had attracted the attention from Russian spies like Alexander Bulatov in 2008 and Victor Podobnyy in 2013, who called Page an “idiot” who got “hooked on Gazprom“?

These links were part of the reason the FBI sought an October 2016 warrant to surveil Page. That warrant has been heavily criticized because it was also partly based on information provided by the former MI6 agent Christopher Steele, who was hired to gather dirt on the Trump campaign. Much of the warrant remains redacted.

An interesting detail is found buried in a Russian public disclosure filed by Gazprombank: Yatsenko graduated in 1984 from Singapore University with a degree in Chinese language.

To anyone who understands life in the former Soviet Union, Yatstenko’s education in Singapore leaps off the page. Studying abroad didn’t just happen for Soviet citizens the way it does in the West, not without approval from the highest circles of power.

Posing as a student was a cover employed by agents of the KGB. A CIA paper noted: “A substantial number of [KGB] students go for a year or more as exchange students or as trainees with Soviet organizations working abroad.”

The year Yatsenko joined Gazprom — 2002 — was a time when the Russian gas giant was heavily recruiting ex-spies. Even the company’s deputy chief executive, Valery Golubev, was an ex-KGB agent.

When Yatsenko left Gazprom in 2010, a curiously-worded report noted that his departure from the company “is most likely connected with the transfer to another job outside the Gazprom group and is not caused by any conflict.”

Yatsenko certainly maintained his influence after partnering up with Page. In December 2016, Yatsenko arranged meetings for Page and Kazakhstan’s ambassador to the United Kingdom, Page told the House intelligence committee.

Yatsenko told Bloomberg he worked with Page to help a Russian investor explore an oil investment in Iraqi Kurdistan, and advising a Chinese investor looking to buy Russian oil assets in Eastern Siberia. There were discussions about natural-gas-powered vehicles in Russia, possibly in partnership with Gazprom, but sanctions put an end to those talks.

“[Page] understands what’s going on in Russia,” Yatsenko told Bloomberg in 2016. “He doesn’t make strong judgments.”