An FBI informant gathered extensive evidence during his six years undercover about a Russian plot to corner the American uranium market, ranging from corruption inside a U.S. nuclear transport company to Obama administration approvals that let Moscow buy and sell more atomic fuels, according to more than 5,000 pages of documents from the counterintelligence investigation.

The memos, reviewed by The Hill, conflict with statements made by Justice Department officials in recent days that informant William Campbell's prior work won't shed much light on the U.S. government's controversial decision in 2010 to approve Russia's purchase of the Uranium One mining company and its substantial U.S. assets.

Campbell documented for his FBI handlers the first illegal activity by Russians nuclear industry officials in fall 2009, nearly an entire year before the Russian state-owned Rosatom nuclear firm won Obama administration approval for the Uranium One deal, the memos show.

Campbell, who was paid $50,000 a month to consult for the firm, was solicited by Rosatom colleagues to help overcome political opposition to the Uranium One purchase while collecting FBI evidence that the sale was part of a larger effort by Moscow to make the U.S. more dependent on Russian uranium, contemporaneous emails and memos show.

"The attached article is of interest as I believe it highlights the ongoing resolve in Russia to gradually and systematically acquire and control global energy resources," Rod Fisk, an American contractor working for the Russians, wrote in a June 24, 2010, email to Campbell.

The email forwarded an article on Rosatom's efforts to buy Uranium One through its ARMZ subsidiary. Fisk also related information from a conversation with the Canadian executives of the mining firm about their discomfort with the impending sale.

"I spoke with a senior Uranium One Executive," Fisk wrote Campbell, detailing his personal history with some of the company's figures. "He said that corporate Management was not even told before the announcement [of the sale] was made.

"There are a lot of concerns," Fisk added, predicting the Canadians would exit the company with buyouts once the Russians took control. Fisk added the premium price the Russians were paying to buy a mining firm that in 2010 controlled about 20 percent of America's uranium production seemed "strange."

At the time, Campell was working alongside Fisk as an American consultant to Rosatom's commercial sales arm, Tenex.

But unbeknownst to his colleagues, Campbell also was serving as an FBI informant gathering evidence that Fisk, Tenex executive Vadim Mikerin and several others were engaged in a racketeering scheme involving millions of dollars in bribes and kickbacks, plus extortion and money laundering.

Justice Department officials confirmed the emails and documents gathered by Campbell, saying they were in the possession of the FBI, the department's national security division and its criminal division at various times over the last decade. They added that Campbell's work was valuable enough that the FBI paid him nearly $200,000, mostly for reimbursements over six years, but that the money also included a check for more than $51,000 in compensation after the final convictions were secured.

The information he gathered on Uranium One was more significant to the counterintelligence aspect of the case that started in 2008 than the eventual criminal prosecutions that began in 2013, they added.

Justice Department spokeswoman Sarah Isgur Flores said Monday that the agency plans to brief members of Congress next week on Campbell's work, the counterintelligence investigation into Russian uranium and the nuclear bribery case. Some issues related to the case are also being reviewed by senior Justice officials, she added.

"The Department of Justice has authorized the confidential informant to disclose to the chairmen and ranking members of the Senate Committee on the Judiciary, the House Committee on Oversight and Government Reform, and the House Permanent Select Committee on Intelligence, as well as staff, any information or documents he has concerning alleged corruption or bribery involving transactions in the uranium market. Until the informant publicly speaks to what he knew or knows about these matters, we are unable to respond further," she said.

Campbell's undercover work helped FBI counterintelligence chronicle a Russian uranium strategy modeled after Moscow's success in creating natural gas monopolies in eastern Europe that strengthened Russia's economy and geopolitical standing after the Cold War, the officials said.

Part of the goal was to make Americans more reliant on Russian uranium before a program that converted former Soviet warheads into U.S. nuclear fuel expired in 2013, according to documents and interviews. Russia's ambitions included building a uranium enrichment facility on U.S. soil, the documents show.

The FBI task force supervising Campbell since 2008 watched as the Obama administration made more than a half dozen decisions favorable to the Russians' plan, which ranged from approving the sale of Uranium One to removing Rosatom from export restrictions and making it easier for Moscow to win billions in new commercial uranium sales contracts. The favorable decisions occurred during a time when President Obama and Secretary of State Hillary Clinton were pursuing a public "reset" to improve relations with Moscow, a plan that fell apart after Russia invaded Ukraine.

Campbell also produced leads for the FBI about suspicious activity inside Iran's and South Africa's nuclear industries, the documents show.

And most importantly, it developed concrete evidence that Tenex - at its Russian leadership's behest - had engaged in a massive racketeering scheme. That evidence led to indictments in 2014 and the convictions of several figures in 2015.

The defendants who pled guilty included Mikerin, the very man Russia sent to the United States to lead its uranium strategy, as well as the head of the American trucking company that moved Russia's uranium around the United States.

Multiple congressional committees recently got permission from the Justice Department to interview Campbell after The Hill reported last month the existence of his informant work.

Lawmakers want to know what the FBI did with the evidence Campbell gathered in real time and whether it warned Obama and top leaders before they made the Russia-favorable decisions, like the Uranium One deal.

Since Campbell's identity emerged in recent days, there have been several statements by Justice officials, both on the record and anonymously, casting doubt on the timing and value of his work, and specifically his knowledge about Uranium One.

The more than 5,000 pages of documents reviewed by The Hill directly conflict with some of the Justice officials' accounts.

For instance, both Attorney General Jeff Sessions in testimony last week and Deputy Attorney General Rod Rosenstein in a letter to the Senate last month tried to suggest there was no connection between Uranium One and the nuclear bribery case. Their argument was that the criminal charges weren't filed until 2014, while the Committee on Foreign Investment in the United States' (CFIUS) approval of the Uranium One sale occurred in October 2010.

"The way I understand that matter is that the case in which Mr. Mikerin was convicted was not connected to the CFIUS problem that occurred two to three years before," Sessions testified to the House Judiciary Committee last week, echoing Rosenstein's letter from a few weeks earlier.

But investigative records show FBI counterintelligence recorded the first illicit payments in the bribery/kickback scheme in November 2009, a year before the CFIUS approval.

Campbell also relayed detailed information about criminal conduct throughout 2010, including the coordinates for various money laundering drops, according to his FBI debriefing reports. The evidence Campbell gathered indicated Mikerin's corruption scheme was being directed by and benefitting more senior officials with Rosatom and Tenex back in Russia, the records show, a claim U.S. officials would make in court years later.

"There is zero doubt we had evidence of criminal activity before the CFIUS approval and that Justice knew about it through [the natural security division]," said a source with direct knowledge of the investigation.

Republican members of Congress have been angered by the Justice Department's first answers because they conflict with the evidence already gathered in their probe.

"Attorney General Sessions seemed to say that the bribery, racketeering and money laundering offenses involving Tenex's Vadim Mikerin occurred after the approval of the Uranium One deal by the Obama administration. But we know that the FBI's confidential informant was actively compiling incriminating evidence as far back as 2009," Rep. Ron DeSantis (R-Fla.) told The Hill.

"It is hard to fathom how such a transaction could have been approved without the existence of the underlying corruption being disclosed. I hope AG Sessions gets briefed about the CI and gives the Uranium One case the scrutiny it deserves," added DeSantis, whose House Oversight and Government Reform subcommittee is one of the investigating panels.

Senate Judiciary Committee Chairman Chuck Grassley (R-Iowa) sent a similar rebuke last week to Rosenstein, saying the deputy attorney general's first response to the committee "largely missed the point" of the congressional investigations.

"The essential question is whether the Obama Justice Department provided notice of the criminal activity of certain officials before the CFIUS approval of the Uranium One deal and other government decisions that enabled the Russians to trade nuclear materials in the U.S.," Grassley said.

Flores said Sessions stands by his testimony. "The Attorney General's testimony is accurate. The criminal case in which Mikerin was convicted and the factual and legal requirements needed to make that case did not address the CFIUS matter," the Justice spokeswoman said.

Similar misinformation surfaced last week in articles by Reuters and Yahoo News in which officials were quoted as casting doubt that Campbell had any information about the Uranium One deal, because Tenex was a different division of Rosatom than the ARMZ subsidiary that bought the mining firm.

But Campbell's FBI informant file shows Uranium One came up several times in 2010 as the sale was pending, partly because Tenex was Rosatom's commercial arm and would be charged with finding markets for the new uranium being mined and enriched both in the United States and abroad.

Campbell himself was directly solicited by his colleagues to help overcome opposition to the Uranium One deal, the FBI informant files show. In an Oct. 6, 2010, email with the subject line "ARMZ + Uranium One," Fisk forwarded a news article outlining Republican efforts to derail the sale.

"The referenced article may present a very good opportunity for Sigma [Campbell's company] to try and remove the opposing influences, if that is something you can do," Fisk wrote the informant, who was also a paid consultant for the company at the time.

The next day, Mikerin was sent an 11-page report laying out the larger Russian nuclear strategy and what Russia wanted to do inside the U.S. to gain advantage in the uranium market. The report cited specific concerns about the political pressure opposing Uranium One if it wasn't overcome. Campbell intercepted the document.

"Some Republicans truly fear the entry of Russia into the U.S. market, as demonstrated by the fact that they are taking steps to block the purchase of Uranium One," the report warned Mikerin. "This effort bears watching as it may provide clues as to the likely political reaction if a Russian entity was going to participate in the construction and operation of a uranium enrichment plant in the U.S."

After Rosatom's sale was approved, Uranium One officials would have direct contact with Tenex and Mikerin, some of which was witnessed by Campbell, the documents show.

For instance, Mikerin forwarded to Campbell an email in 2012 from a Uranium One executive suggesting the planned construction of a new nuclear reactor near Augusta, Ga., might prove a good opportunity for both Uranium One and Tenex to expand their business, the documents show.

Campbell's debriefing files also show he regularly mentioned to FBI agents in 2010 a Washington entity with close ties to Bill and Hillary Clinton that was being paid millions to help expand Tenex's business in the United States. The entity began increasing its financial support to a Clinton charitable project after it was hired by the Russians, according to the documents.

Campbell engaged in conversations with his Russian colleagues about the efforts of the Washington entity and others to gain influence with the Clintons and the Obama administration. He also listened as visiting Russians used racially tinged insults to boast about how easy they found it to win uranium business under Obama, according to a source familiar with Campbell's planned testimony to Congress.

Uranium One was a large enough concern for the informant that he confronted one of his FBI handlers after learning the CFIUS had approved the sale and that the U.S. had given Mikerin a work visa despite the extensive evidence of his criminal activity, the source said.

The agent responded back to the informant with a comment suggesting "politics" was involved, the source familiar with Campbell's planned testimony said.

Justice officials said federal prosecutors have no records that Campbell or his lawyer made any allegations about the Uranium One deal during his debriefings in the criminal case that started in 2013, but acknowledged he collected evidence about the mining deal during the FBI counterintelligence investigation that preceded it.

In recent days, news media including The Washington Post and Fox News anchor Shepard Smith have inaccurately reported another element of the story: that Uranium One never exported its American uranium because the Obama administration did not allow it.

However, the Nuclear Regulatory Commission authorized Uranium One to export through a third party tons of uranium to Canada for enrichment processing, and some of that product ended up in Europe, NRC documents state.

A Uranium One executive acknowledged to The Hill that 25 percent of the uranium it shipped to Canada under the third-party export license ended up with either European or Asian customers through what it known in the nuclear business as "book transfers."

But the recent leaks that have most concerned congressional investigators occurred in a Yahoo story late Friday, in which Justice officials anonymously questioned Campbell's credibility and suggested they had to alter their criminal case against Mikerin in 2015, eventually striking a plea deal, because they feared he would be a "disaster" as a trial witness.

The FBI informant file, however, paints a different picture. After Mikerin pleaded guilty and was sentenced to 48 months prison in December 2015, the FBI took Campbell out to a celebratory seafood dinner and delivered a handsome reward: a check for $51,046.36 dated Jan. 7, 2016, a copy of which was obtained by The Hill.

A source directly familiar with the FBI's evidence said the primary reason prosecutors working under Rosenstein, then the U.S. attorney in Maryland, changed course in the case was because of concerns their initial indictment miscast Campbell's role in the investigation.

The original indictments and affidavits portrayed Campbell as a "victim" who became a confidential witness after the Russians tried to "extort" him in summer 2009 into a kickback scheme, court records show.

In fact, Campbell was an informant deeply controlled by FBI counterintelligence starting when he signed a nondisclosure agreement in January 2008, more than a year before Mikerin engaged him in the criminal activity, the FBI's records show.

Campbell was inserted inside Mikerin's world specifically to look for criminal activity and other harmful national security actions by the Russians, starting with undercover work he performed as a consultant contracting with a lobbying firm in 2008 and then inside Tenex starting in 2009, according to documents and memos.

Campbell's regular debriefings dating to 2008 show the nature of some of his undercover work, including making surreptitious recordings and collecting documents well before the first money laundering started inside Tenex in 2009. He also had a long history of collaboration with U.S. intelligence, including the FBI, that predated his case, sources told The Hill.

To facilitate his cover, Campbell made a cash payment in summer 2009 to a Russian consultant after he secured the Tenex consulting contract. His Russian colleagues demanded he hire the overseas consultant to better learn the company's strategy and how the Russians preferred to receive their consulting reports, sources said.

The transaction later worried prosecutors in the criminal case because they feared it might muddy their case of extortion against Mikerin because the voluntary payment was made only shortly before the kickback demands started, the sources said.

The prosecutors also faced another concern about the case unrelated to Campbell, the sources said.

When Fisk - one of the main targets of their bribery investigation - died in 2011, the FBI did not execute a grand jury subpoena to capture all of his evidence. Instead, agents asked his widow for permission to voluntarily search his computer hard drive and remove the documents the agents wanted.

The hard drive was subsequently discarded before the criminal charges were filed, leaving it unavailable for defense lawyers to search, the sources said. Defense lawyers pounced on the revelation late in the case, court records show.

At the time, Fisk was a larger than life figure inside the Russian nuclear industry, having headed the trucking firm that moved uranium across the United States on behalf of Rosatom. Campbell helped the FBI document that both Fisk, starting in 2004, and a successor, starting in 2011, at the trucking firm were paying bribes to the Russians, the records show.

During 2010, Fisk was transitioning from the trucking firm to become a key strategist for Tenex and Mikerin, advising them on the Russian nuclear industry's aggressive push to expand its business in the United States.

Sources said the recasting of the prosecution in 2015 had much to do with avoiding exposing the extensive nature of the FBI counterintelligence operations that involved Campbell.

"This isn't really about his credibility or work, which generated leads we relied on well into 2016. Often times, CI investigations are focused first on monitoring and stopping activity that threatens U.S. security and the consequences to later criminal case are a secondary concern," said one source familiar with the probe. "That's the reality of a dirty business."

Asked whether the criminal side of the Justice Department knew about Campbell's work, including its origins to 2008 and its possible ties to Uranium One, a source with direct knowledge said the prosecutors acquired all of Campbell's emails as part of a 2015 agreement he signed. Justice also had access to Campbell's emails recovered from Fisk's computers in 2011 as well as documents Campbell gave during debriefings that started in 2008, the source added.

The sources familiar with the full body of Campbell's work said they expect he can provide significant new information to Congress.

"Will he be able to prove that we knew Russia was engaged in criminal conduct before Uranium One was approved? You bet," the source said. "Were the Russians using political influence and pulling political levers to try to win stuff from the U.S. government? You bet. Was he perfect? No one in this line of work is. But we were focused on much larger issues than just that."

Campbell endured significant stress during his time undercover and suffered a handful of episodes related to drinking, resulting in two misdemeanor reckless driving charges and one misdemeanor driving under the influence, his lawyer said.

Attorney Victoria Toensing told The Hill that the FBI was fully aware of the drinking incidents and continued to use her client for many years after.

"Until he began working undercover for the U.S. government in his early 60s, Mr. Campbell had an unblemished driving record," she said. "However, the pressure of living a double life and being threatened by the Russians if he violated their trust took a toll.

"Additionally, there were numerous occasions where he was required to meet socially with the Russians, who were prodigious imbibers of vodka. Any refusal by him to participate could have compromised his cover. Mr. Campbell has not had any driving or drinking issue since 2014 when he ceased working undercover."

Updated on February 19, 2020 at 7:56 a.m.

Disclosure: Victoria Toensing is an attorney who represents John Solomon.