Sen. Lindsey Graham on Tuesday sent a letter to FBI Director Christopher Wray demanding the names of the individuals who gave a 2018 briefing to the Senate Intelligence Committee in which Graham alleges the FBI lied about the reliability of the infamous Steele Dossier.

The dossier, which was the main basis for the Foreign Intelligence Surveillance Act (FISA) warrant against former Trump aide Carter Page, makes a variety of salacious claims about President Trump, many of which are unverified.

The FBI interviewed the main subsource ex-British spy Christopher Steele used to produce the dossier in 2017, and the subsource reportedly said Steele had exaggerated his claims. But then in 2018, according to a document released Sunday by the Senate Judiciary Committee, which Graham chairs, the FBI seemingly told the Senate Intelligence Committee in a briefing that there was no reason to doubt the Steele Dossier or the information allegedly from the subsource.

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"In 2017, the FBI interviewed the Primary Sub-source three times, including one interview that occurred over three days in January 2017. The result of those interviews was that the Primary Sub-source largely discredited the dossier and the way that Steele reported and characterized the information the Primary Sub-source had given him," Graham said in the letter to Wray.

"Yet, in the outline of FBI’s briefing to the Intelligence Committee," Graham continues, "it states that: (1) the Primary Sub-source 'did not cite any significant concerns with the way his reporting was characterized in the dossier to the extent he could identify it'; (2) '[a]t minimum, our discussions with [the Primary Sub-source] confirm that the dossier was not fabricated by Steele'; and (3) the Primary Sub-source 'maintains trusted relationships with individuals who are capable of reporting on the material he collected for Steele.'"

Graham broke the news about the briefing document, which was given to the Senate Judiciary Committee by Attorney General William Barr, during an interview with Fox News' Maria Bartiromo on "Sunday Morning Futures."

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"They did to the Senate Intel Committee what they did to the FISA court," Graham said. "They misled the hell out of them. They said there's no evidence from the subsource to suggest that Steele fabricated anything in the dossier."

Graham said in the interview with Bartiromo that he would get to the bottom of the issue.

"Somebody needs to go to jail for this," Graham said. "This is a second lie. This is a second crime. They lied to the FISA court. They got rebuked, the FBI did, in 2019 by the FISA court, putting in doubt all FISA applications ... a year before, they're lying to the Senate Intel Committee."

He added: "I'm gonna find out who did that briefing, and whoever it is, they're in trouble."

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That's just what Graham's letter to Wray aims to do -- he asks the FBI director for the names and titles of every person who worked on the outline his committee released Sunday, all of the FBI employees who were at the Senate Intelligence Committee briefing and any documents the FBI has that pertain to congressional briefings about the dossier, the Russia investigation and the FISA applications to surveil Page.

Graham's letter is not a subpoena but a request, meaning that Wray is not legally obligated to comply. But Wray -- who was in charge at the time of the 2018 briefing -- is a Trump appointee who, despite the charged politics surrounding the Department of Justice, has largely been able to keep himself out of the political fray.

Wray, however, does face a subpoena from Sen. Ron Johnson, R-Wis., for "all records related to the Crossfire Hurricane investigation." Crossfire Hurricane was the probe into Russian election interference that investigated Trump associates like Page and former National Security Advisor Michael Flynn. Johnson chairs the Senate Homeland Security Committee.

Fox News' Brooke Singman contributed to this report.