When former President Bill Clinton received a $500,000 check from a Kremlin-linked bank in 2010 to give a speech in Moscow it served, to the FBI, as further evidence the Russians had unleashed an influence campaign designed to get access to Secretary of State Hillary Clinton.

The Hill newspaper reported Sunday night that the FBI had been keeping close tabs on a Russian spy network that was trying to inch closer to the Clintons at the dawn of the Obama administration, with one spy – who was eventually arrested and deported – briefly posing successfully as an American accountant and working for a top Democratic donor.

FBI agents were 'surprised by the timing and size,' the Hill wrote, of Bill Clinton's half-million dollar speech, which has raised conflict-of-interest questions about Hillary Clinton, as the transaction occurred around the same time she was being asked to sign off on a uranium deal, which gave Russia 20 percent of the U.S.'s deposits.

When ex-President Bill Clinton (right) received a $500,000 check in 2010 from a Kremlin-linked bank to give a speech, it served as evidence to the FBI that the Russians had unleashed an influence campaign designed to get closer to Hillary Clinton (left), as secretary of state

Russian spy Cynthia Murphy (left) was considered a bigger threat to U.S. authorities than model Anna Chapman (right) who was also busted, as Murphy had gained employ from a Democratic donor with ties to Hillary Clinton

There is no evidence that the FBI thought the Clintons did anything illegal – and many of the moves the Russians made were also in plain sight, such as the hiring of lobbyists.

But there was proof the Russians were trying to get access to the former first couple.

'There is not one shred of doubt from the evidence that we had that the Russians had set their sights on Hillary Clinton's circle, because she was the quarterback of the Obama-Russian reset strategy and the assumed successor to Obama as president,' a source who knew of the FBI's evidence told the Hill.

The most criminal effort came in the form of a Russian spy named Cynthia Murphy, who was pretending to be an accountant in New Jersey.

Murphy was one of a handful of Russian spies unmasked in 2010, alongside model Anna Chapman.

In 2012, ABC News reported that what triggered the FBI to round up and oust the spies was that one had gotten too close to a sitting U.S. cabinet official.

While fingers had originally pointed at Chapman, ABC reported it was Murphy who was the problem, as she had been in contact with a 'personal friend' of Hillary Clinton, identified as fundraiser Alan Patricof.

Conversations between Clinton's deputy chief of staff Huma Abedin and State Department Dennis Cheng show that Patricof wanted to give Clinton a heads up as the story was about to become public, emails released through Citizens United show.

However, when the Russian spy ring story broke in 2010, Clinton's office issued a statement saying there was 'no reason to think the secretary was a target of this spy ring.'

Frank Figliuzzi, the former FBI assistant director for counterintelligence, who supervised the declassification records about the spy ring, told the Hill that wasn't the case.

'In regards to the woman known as Cynthia Murphy, she was getting close to Alan, and the lobbying job. And we thought this was too close to Hillary Clinton,' he explained.

'So when you have the totality of the circumstance, and we were confident we had the whole cell identified, we decided it was time to shut down their operations,' he said.

A day after the ring of Russian spies was arrested, Bill Clinton accepted the $500,000 check, which caught the FBI's attention, the Hill learned.

Clinton gave a 90-minute speech to Renaissance Capital, a Kremlin connected bank that was promoting the Uranium One Deal's stock.

Other entities associated with the uranium deal had also given money to the Clinton Foundation.

Since so much of the U.S.'s uranium deposits would go to Russia, agency heads including Hillary Clinton at State and Attorney General Eric Holder at the Justice Department had to sign off on it – which they did.

President Trump has drawn attention to the uranium story as of late, telling reporters in the Oval Office last week that 'that's your real Russia story.'

Bill Clinton's longtime spokesman Angel Urena told the Hill that the ex-president never discussed the issues pending before the State Department while he was visiting Russia, nor did the financial transactions given to him and his family foundation influence Hillary Clinton's decision as secretary of state.

Hillary Clinton's spokesman Nick Merrill declined telling the Hill if the then-secretary of state was briefed on the Russian spies' efforts.

Focusing on the spy ring, he suggested, was a right-wing distraction from the real question at hand, Russia's meddling in the 2016 election, which was meant to hurt Hillary Clinton and help President Trump.

'Nothing has changed since the last time this was addressed, including the right's transparent attempts to distract from their own Russia problems, which are real and a grave threat to national security,' Merrill told the Hill.