A graduate of a prestigious physics faculty, Mr. Deripaska rose to wealth in the 1990s, strong arming his way to a virtual monopoly over the Russian aluminum industry. When it placed sanctions on him and his companies last year, the Treasury Department cited his links to the Russian government, saying he profits from the country’s “malign activity around the globe.”

Even while keeping a low profile, he pursued a costly lobbying and legal effort to assert his innocence. Initially, this revolved around sanctions on his businesses, and with the help of a global influence-buying operation he did persuade the Treasury Department to lift sanctions on his aluminum empire in January.

Mr. Deripaska now wants to escape the personal sanctions, which hinder his ability to do business in the United States. Last month, he filed a lawsuit seeking the removal of those sanctions, which he claims have cost him $7.5 billion.

The conclusion that members of the Trump campaign had not colluded with Russians, Mr. Deripaska said, suggested the tide was shifting in campaigns of innuendo and guilt through leaks to the news media. If so, he said, the American justice system might also eventually clear him of other accusations never proven in court, such as ordering a contract murder.

“I always believe in justice,” said Mr. Deripaska, whose lawyers have frequently fought to keep suits from being brought in American courts, saying they have no jurisdiction. “For us outside the United States, Mueller signals that the U.S. legal system is still alive, it still exists.”

Mr. Deripaska had faced scrutiny for financial entanglements with a former Trump campaign chairman, Paul J. Manafort, who in July 2016 reportedly asked an associate to offer Mr. Deripaska a private briefing on the presidential race, in hopes of settling a $26 million lawsuit stemming from a failed investment venture. The two had been business associates a decade ago. Mr. Deripaska had denied receiving the offer, but had not addressed these matters in detail while the investigation continued.