Paul Manafort's work as a political consultant for pro-Russian causes not only took place over a much longer time than previously reported — about 10 years — it also often involved the same powerful Russian oligarch, The Wall Street Journal reported Wednesday.

That man, Oleg Deripaska, was involved not only in Manafort's work in Ukraine, but also in Georgia and Montenegro, according to the Journal.

The publication also said Manafort's work started as early as 2004 and continued to 2015, the year before he signed on as then-candidate Donald Trump's campaign chairman.

Manafort lost that job in August 2016 for failing to fully disclose the work he had done in Ukraine.

Congressional investigators probing Russia's attempts to influence the U.S. presidential election want to know more about Manafort's ties to Deripaska, the Journal said, but have declined Deripaska's offer to testify in exchange for immunity because they do not want to hinder the FBI investigation.

Deripaska's business ventures have been closely tied to the interests of Russian President Vladimir Putin, with Deripaska telling the Financial Times in 2007, "I don't separate myself from the state. I have no other interests."

He was at one time banned from traveling to the United States over the belief he was tied to organized crime in the aftermath of the Soviet Union's downfall. Deripaska has denied those reports.

He also denies having financial ties to Manafort, and sued the Associated Press for defamation over an article in March that reported that he did.

"Mr. Deripaska never had any arrangement, whether contractual or otherwise, with Mr. Manafort to advance the interests of the Russian government," according to a court filing in May. "Mr. Deripaska severed relations with Mr. Manafort many years ago."

According to the Journal, the two men did have a falling out, and cut ties in 2014, but Manafort continued working in Ukraine.