The mysterious role that political intelligence firm Fusion GPS played in 2016 took a new turn Tuesday as it was revealed the firm's cofounder met with a Kremlin-linked lawyer at the time e met with the president's son about dirt on Hillary Clinton.

Fusion GPS cofounder Glenn Simpson, a former Wall Street Journal reporter, met with Kremlin-linked lawyer Natalia Veselnitskaya both before and after her meeting with Donald Trump Jr., Fox News reported.

He was with her just hours before the June 9, 2016 meeting, at her side in a Manhattan federal court, according to the report.

The firm also worked on behalf of Russian firm Prevezon, which was fighting sanctions after allegedly committing an alleged money laundering scheme.

BUSY: Russian lawyer Natalia Veselnitskaya met with Glenn Simpson of Fusion GPS both before and after her meeting with Donald Trump Jr. at Trump Tower in June 2016, it was reported

Veselnitskaya has crusaded for years to try to roll back the Magnitsky Act, which imposed sanctions in response to the killing of Sergei Magnitsky, who died in a Russian prison after exposing an alleged fraud.

Court records and emails reviewed by the network corroborate the statement by a source, who also said they were together after the infamous Trump Tower meeting.

That meeting occurred after a British music PR dangled the possibility of dirt on Hillary Clinton, and the president's eldest son took him up on the offer.

Glenn Simpson is a cofounder of Fusion GPS, which funded research for the notorious dirty dossier on Donald Trump

Donald Trump Jr. met with the Kremlin-linked lawyer at Trump Tower in June 2016

But Fusion GPS was playing multiple sides. It collected payments from a Democratic lawyer representing the Hillary Clinton campaign and the Democratic National Committee that funded research for the infamous 'dirty dossier' of unverified opposition research about Donald Trump.

The Democrats began funding the dossier research in April 2016, picking up the ball after a Republican donor had earlier funded research.

Among the most salacious claims was a discredited account of Trump's supposed conduct in a Moscow hotel room with prostitutes.

Special counsel Robert Mueller is probing the June 2016 Trump Tower meeting.

Another attendee of the Trump Tower meeting was , Rinat Akhmetshin, a former Soviet counter-intelligence officer. Trump son-in-law Jared Kushner and former campaign chair Paul Manafort also were present.