The Senate Judiciary Committee is investigating whether top officials knew that a case of Russian corruption had been uncovered by the FBI when the Obama administration approved a controversial uranium deal with the Russians — a development that could turn the long-standing “Russia scandal” against top Democratic figures.

According to The Hill, committee aides sent requests this week for more information to 10 federal agencies involved in the approval of the partial sale of the Canadian mining company Uranium One to Russia. Those letters are believed to ask about when figures involved in the deal knew about FBI investigations into alleged Russian nuclear corruption.

This comes after the outlet published an in-depth investigation reporting that the FBI had gathered evidence that Russian nuclear industry officials were engaged in bribery and extortion as part of a broader plan to grow Russia’s energy business in the U.S in 2010.

Also, the Hill reports that the controversial Clinton foundation is referenced in the FBI investigation:

[The FBI] also obtained an eyewitness account — backed by documents — indicating Russian nuclear officials had routed millions of dollars to the U.S. designed to benefit former President Bill Clinton’s charitable foundation during the time Secretary of State Hillary Clinton served on a government body that provided a favorable decision to Moscow, sources told The Hill.

The report is likely to resurrect serious concerns of pay-to-play regarding the Clinton’s and the Clinton Foundation that dogged Hillary Clinton during her doomed presidential campaign. Clinton denied repeated and widely reported claims that foreign governments pumped money into her charitable arm as a way of influencing her when she served as secretary of state during the Obama administration.

When the Justice Department was informed, instead of bringing charges in 2010, it lingered on it for four years before bringing charges — leaving lawmakers and the public at large unaware of evidence of major Russian corruption involving nuclear issues.

In this period where the Justice Department was sitting on the corruption evidence, the multi-agency Committee on Foreign Investment in the United States (CFIUS) approved the Uranium One deal. That committee included then-Attorney General Eric Holder and then-Secretary of State Hillary Clinton.

The Hill reports that during that period, the Obama administration also approved a Rosatom subsidiary to sell commercial uranium. to the U.S. nuclear power plants. This occurred in 2011, also during the period when the Justice Department was believed to be investigating the Russian nuclear corruption.

Senate Judiciary Committee Chairman Chuck Grassley (R-IA), who has consistently raised questions about the Uranium One deal, said he was not convinced by Obama administration claims that there was no basis to block it.

“I am not convinced by these assurances,” Grassley wrote in a letter to the Homeland Security Department last week. “The sale of Uranium One resulted in a Russian government takeover of a significant portion of U.S. uranium mining capacity. In light of that fact, very serious questions remain about the basis for the finding that this transaction did not threaten to impair U.S. national security.”

The Hill reports that a Wednesday committee hearing, while scheduled to discuss other topics, was likely to see Grassley question Attorney General Jeff Sessions on the controversy.

Grassley’s letters have been sent to federal agencies whose heads were involved in the vote on the Uranium One deal, and ask if they knew about the FBI probe when they voted on the deal.

Adam Shaw is a Breitbart News politics reporter based in New York. Follow Adam on Twitter: @AdamShawNY