Fusion GPS co-founder Glenn Simpson might have lied under oath to Senate and House investigators when he said he never communicated with the FBI about the dossier that the Hillary Clinton campaign and the Democratic National Committee hired him to produce.

FBI memos that are now being turned over to Congress include an email written by FBI agent Peter Strzok that shows the FBI received a version of the dossier from Simpson, before it was published online by BuzzFeed in January 2017.

“Our internal system is blocking the site,” Strzok wrote of the copy of the dossier published by BuzzFeed. “I have the PDF via iPhone but it’s 25.6MB. Comparing now. The set is only identical to what McCain had. (it has differences from what was given to us by Corn and Simpson.).”

The Hill‘s John Solomon first reported on Strzok’s email, which was sent around the time BuzzFeed published a copy of the dossier on January 10, 2017.

However, Simpson had denied twice last year to House and Senate investigators that he had ever communicated with the FBI about the dossier or provided them with a copy of it.

Senate Judiciary Committee investigators asked Simpson during closed-door testimony last year, “Mr. Simpson, did anyone from Fusion ever communicate with the FBI regarding information in the memoranda or other allegations regarding Mr. Trump, and his associates?”

Simpson responded, “No, no one from Fusion ever spoke with the FBI, to the best of my knowledge.”

He also said he was unaware of any version of the dossier being given to the FBI. “I don’t know that there was a version provided to the FBI,” he said.

Simpson also denied to House investigators he ever approached the FBI with information in the dossier.

A House investigator asked Simpson: “Did you at any time approach the FBI directly regarding this information or your findings?”

“I didn’t approach the FBI,” Simpson responded.

It is unclear whether Strzok misstated Simpson as a source for the dossier, or whether Simpson misled Congress.

Strzok’s email also shows some of the multiple channels through which the dossier was being fed to the FBI.

Sen. John McCain (R-AZ) has admitted to meeting an associate of Christopher Steele — the ex-British spy hired by Fusion GPS to work on the dossier — in Halifax, Nova Scotia, in December 2016, and arranging for his associate, David Kramer, to travel to London to obtain a copy of the dossier to give to the then-FBI Director James Comey.

How Buzzfeed obtained an actual copy of the dossier is unknown, but Strzok’s email revealed that it was the same version as the one given McCain. Buzzfeed’s set “is only identical to what McCain had,” Strzok wrote.

The “Corn” that Simpson was referring to is Mother Jones reporter David Corn. Although Corn never published the dossier, he wrote an article on Oct. 31, 2016, entitled, “A Veteran Spy Has Given the FBI Information Alleging a Russian Operation to Cultivate Donald Trump.” He told The Hill he sent the dossier to the FBI after the election, hoping to obtain some verification of it from the FBI.

There could have also been other channels used to pass on the dossier’s findings to the FBI.

CIA Director John Brennan reportedly briefed during the summer of 2016 then-Senate Minority Leader Harry Reid (D-NV), who then wrote a letter to Comey asking him to investigate them. The Hill‘s Solomon wrote:

The significance of Strzok’s email is obvious to investigators who reviewed it in recent days. The FBI is supposed to be immune to manipulation by circular information flows, especially with sensitive investigations such as evaluating whether a foreign power tampered with an American election. Yet, in this case, the generally same information kept walking through the FBI’s door for months — recycled each time by a new character with ties to Hillary Clinton or hatred for Trump — until someone decided they had to act.

As an investigator told Solomon: “The dossier and its related dirt was on a circular flight path aboard a courier service called ‘Air Clinton,’ and the FBI kept signing for the packages.”

“It’s all the sort of recycling that, in another context, might make an environmentalist happy. But it’s exactly the sort of circular intelligence-gathering and political pressure that the FBI is supposed to reject,” Solomon wrote.

The FBI would later use the dossier, as well as a Yahoo News report based on the dossier’s findings, to justify obtaining a surveillance warrant on former Trump campaign adviser Carter Page in October 2016, right before the election. The dossier made an unverified claim that Page had met with two senior Russian officials during a publicized trip in July 2016.

The House Intelligence Committee is investigating how the dossier was used by Justice Department and FBI officials during its investigation of the Trump campaign and any potential abuses.