The scion of a venerable New York family descended from 19th century railroad and shipping tycoon Cornelius Vanderbilt says he was bamboozled by a U.S. private equity firm secretly fronting for a cabal of wealthy Russian oligarchs with direct ties to Vladimir Putin.

A group of financiers that Carter Burden III thought were providing a much-needed financial boost to his successful cloud services provider, Logicworks, were in fact responsible for its eventual collapse, forcing a fire sale for a fraction of the company’s worth, according to a newly filed fraud lawsuit.

What Burden didn’t know, and about which he says he was fed an ongoing string of lies by intermediaries, was that Pamplona Capital Management, the outfit that in 2016 bought a majority stake in Logicworks, was “less than a proper investment fund and more of a shell company” created to invest the personal fortunes of Mikhail Fridman, Petr Aven, German Khan, and Alexey Kuzmichev, according to him. The four oligarchs are all said to be connected to the Kremlin, and at least one has been credibly accused of international money laundering. (None of them are named as defendants in Burden’s suit.)

“For years, Pamplona’s representatives lied to and obscured the truth from Mr. Burden to prevent him from learning the truth,” states the 22-page lawsuit, which was filed in Manhattan Supreme Court on Friday and added to the public docket Saturday morning. “Fights with regulators were conveniently explained away. Concerns from banks and outside investors were swept aside. And questions from Mr. Burden were either deflected or simply falsely answered.”

Unaware of his new business partners’ true identities, Burden’s Logicworks continued to thrive—until Russia invaded Ukraine early last year, the suit says.

Soon, the four oligarchs with whom Burden, 55, had unwittingly gone into business became international pariahs cut off from the global banking system. Suddenly, Burden found his company had become kryptonite to banks, investors, and government regulators, according to his lawsuit.

On Feb. 28, 2022, Fridman, founder of the U.S.-blacklisted Alfa Bank, along with Alfa Bank president Aven— who served as…