An American businessman who went undercover for the FBI was blocked during the Obama administration from telling Congress what he knew about Russia’s efforts to influence the Clintons’ and Obama administration decisions, according to a report.

Attorney Victoria Toensing, a former Reagan Justice Department official and former chief counsel of the Senate intelligence committee, told The Hill that she is trying to get the Trump administration or the FBI to free her client to talk.

“All of the information about this corruption has not come out,” Toensing said.

She said her client possesses “specific allegations that Russian executives made to him about how they facilitated the Obama administration’s 2010 approval of the Uranium One deal and sent millions of dollars in Russian nuclear funds to the U.S. to an entity assisting Bill Clinton’s foundation.”

At the time, Hillary Clinton was secretary of state and serving on the government panel that approved the deal, the lawyer said. Bill Clinton accepted $500,000 Russian speaking fees in 2010 and collected millions more in donations from parties with a stake in the Uranium One deal. The Clintons and the Obama administration have denied that had any influence on the deal.

But Toensing said her client can also testify that FBI agents made comments to him suggesting political pressure was exerted, and that there was specific evidence that could have scuttled approval of the Uranium One deal if it became public.

“There was corruption going on and it was never brought forward. And in fact, the sale of the uranium went on despite the government knowing about all of this corruption. So, he’s coming forward. He wants the right thing to be done, but he cannot do it unless he is released from the NDA,” she told the outlet.

Toensing said her client was asked by the FBI to sign a non-disclosure agreement (NDA) to prevent him from talking to Congress, and has memos showing how the Obama Justice Department threatened him when he attempted to file a lawsuit to recover monies Russians stole from him and which could have drawn attention to the Russian corruption during the 2016 election.

The department threatened to bring a criminal case against him for violating the NDA, she said. The Hill also said it obtained emails from a civil attorney working with the witness that described the pressure the department was exerting on him to stay quiet.

“The government was taking a very harsh position that threatened both your reputation and liberty,” the civil lawyer wrote in one email, according to the outlet. In another, she wrote: “As you will recall the gov’t made serious threats sufficient to cause you to withdraw your civil complaint.”

The Hill on Tuesday revealed a wide-ranging FBI probe into Russian nuclear industry corruption facilitated by an American consultant who worked for Russian energy giant Rosatom’s Tenex subsidiary to grow Moscow’s uranium business inside the U.S.

The efforts included winning approval for Rosatom’s purchase of Canada-based Uranium One’s American uranium assets, and securing approval to sell uranium to the United States Enrichment Corporation and winning billions in new U.S. utility contracts.

Court records show that Toensing’s client went to the FBI immediately after Russian officials asked him to engage in illegal activity in 2009, according to the report. Working undercover, the client made kickback payments to the Russians with the approval of the FBI.

As a result of the client’s work, the U.S. was able to crack a “multibillion dollar racketeering scheme by Russian nuclear officials on U.S. soil that involved bribery, kickbacks, money laundering and extortion,” The Hill reported.

“In the end, the main Russian executive sent to America to expand Vladimir Putin’s nuclear business, an executive of an American trucking firm and a Russian financier from New Jersey pled guilty to various crimes in a case that started in 2009 and ended in late 2015,” it reported.