The FBI told Christopher Steele they were looking into Trump campaign associate George Papadopoulos, an insight about the bureau's secretive 2016 Trump-Russia investigation the British ex-spy passed along to Fusion GPS.

New details about Steele’s close relationship with the FBI — and the willingness of the former MI6 agent and Orbis Business Intelligence co-founder to pass information to the opposition research firm — were revealed by Fusion GPS co-founders Glenn Simpson and Peter Fritsch in their new book, Inside the Steele Dossier and the Fusion GPS Investigation of Donald Trump.

Steele described a 2016 meeting at a secure facility in Rome with a “phalanx” of FBI agents weeks before the presidential election, including Steele’s FBI conduit Michael Gaeta. Gaeta worked with Steele for years on a Russia-related FIFA corruption case, was serving as the U.S. embassy in Rome’s legal attaché to Italy’s security services, and was briefed by Steele about his dossier findings in London in early July 2016.

Papadopoulos wasn’t interviewed by the FBI until January 2017, but Steele and Fusion GPS learned he was being looked at months earlier.

“The session yielded an important bit of intelligence for Fusion,” Simpson and Fritsch wrote of the meeting. “FBI agents surprised Steele by asking him what he knew about Trump adviser George Papadopoulos. Nothing, it turned out: none of Steele’s sources had ever reported on him. Steele inferred that Papadopoulos was somehow important within the overall inquiry, but they didn’t say exactly why they thought that, only that they had additional source reporting to back that up.”

The Fusion founders wrote that “Steele passed that important tidbit on to Simpson, who found it reassuring: The FBI had developed information that independently corroborated Steele’s own reporting, and they seemed to trust him enough to run it by him.”

Steele's salacious and unverified dossier, which was published in early 2017 by Buzzfeed, has been widely criticized, including by the Trump administration's former Russia expert on the National Security Council, Fiona Hill, who said it “very likely” contained Russian disinformation.

The FBI also told Steele about their justification for launching their investigation.

“Apparently someone at the Trump campaign bragged to someone else that the Russians were providing information hacked from the Democrats to the campaign,” Steele told Simpson. “Whoever heard it decided to blow the whistle to the FBI.”

The FBI declined a request for comment from the Washington Examiner.

Papadopoulos, who pleaded guilty in 2017 to making false statements to the FBI and served 12 days in prison last year, claims he was told by the mysterious Maltese academic Joseph Mifsud in London in 2016 the Russians had damaging information on Democratic presidential candidate Hillary Clinton. Papadopoulos conveyed this over drinks to Australian diplomat Alexander Downer, and Australia alerted the United States about the conversation. This allegedly sparked the FBI's counterintelligence investigation, dubbed Crossfire Hurricane, in late July 2016, which was later wrapped into special counsel Robert Mueller's Russia investigation.