A London-based banker who led sanctions against the Russian government is accusing Fusion GPS of trying to assist the Russian government’s efforts to have him "imprisoned or killed."

"Browder made the allegation in response to the recent revelation that Fusion GPS and its founder Glenn Simpson compiled what he says is false information about him that was given to Yuri Chaika, Russia’s prosecutor general, and to Donald Trump Jr. during the infamous June 2016 Trump Tower meeting," The Daily Caller reports.

Bill Browder, who was one of the main drivers behind the Magnitsky Act, says that if the revelations are true, then it means that Fusion GPS was actively assisting the Kremlin in their efforts to silence him.

"If it is true that Glenn Simpson was supplying information about me to the Russian government, it’s far more serious than smear campaigning or Foreign Agents Registration Act violations," Browder said. "It would mean that Simpson was assisting the Putin regime in their plot to get me back to Russia to have me imprisoned and killed."

Browder’s lawyer, Sergei Magnitsky, became a prisoner of the Russian government and died in prison after alleged abuse and mistreatment. In 2012, the United States Congress passed the Magnitsky Act which "targets Russian human-rights abusers: It freezes their assets and deprives them of visas," the National Review explains.

The Daily Caller notes that it was only discovered last week that "information Fusion collected on Browder was shared directly with Chaika, whose position is the Russian equivalent of the U.S. attorney general."

A law firm representing Russian businessman Denis Katsyv — who faced penalties because of the Magnitsky Act — hired Fusion GPS to conduct research on Browder.

This is not the first time Fusion GPS has been accused of conducting dirty work. The firm is accused of falsely smearing a Venezuelan journalist as a "pedophile," "extortionist," and "drug trafficker," after he criticized one of Fusion’s clients.

"I believe that Fusion GPS's business is to do basically whatever the paymasters tell them to do," Venezuelan journalist Alek Boyd told Fox News. "They are particularly good at spreading misinformation, disinformation, and smears."