Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., said Sunday former FBI deputy director Andrew McCabe will testify on Oct. 6, adding that "something else ... more damning" is coming amid fallout over the controversial Steele dossier.

Graham also wants to hear testimony from FBI agent William Barnett, he told "Sunday Morning Futures." Barnett served on Robert Mueller’s team and said he believed the special counsel’s prosecution of former White House national security adviser Michael Flynn was part of an attitude to “get Trump."

FBI OFFICIAL ON MUELLER TEAM SAID FLYNN PROSECUTION HAD 'GET TRUMP' ATTITUDE

"When you look at what Mr. Barnett says and the way they defrauded the FISA [Foreign Intelligence Surveillance Act] court, you get a clear picture that these people are on a mission to go after Trump," Graham said on Sunday. "Can you imagine if the shoe were on the other foot, that if the Republicans had done this? There's a day of reckoning coming. Just stay tuned, and there's more coming. There's something else coming, more damning than this, believe it or not."

In this Dec. 17, 2018, file photo, former FBI Director James Comey speaks to reporters on Capitol Hill Washington. (AP Photo/J. Scott Applewhite, File)

In this Dec. 17, 2018, file photo, former FBI Director James Comey speaks to reporters on Capitol Hill Washington. (AP Photo/J. Scott Applewhite, File)

McCabe's former boss, ex-FBI Director James Comey, will testify before the Judiciary Committee on Wednesday. Graham would also like to hear from former FBI agent Peter Strzok, who was ousted from his position after the discovery of text messages containing anti-Trump comments, the senator said Sunday.

Sources say U.S. Attorney John Durham’s team, which is reviewing the origins of the Trump-Russia probe, is unlikely to release a report or indictments before Election Day, "Sunday Morning Futures" host Maria Bartiromo first reported Sunday.

Graham said he didn't know about the timing of a report from Durham.

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"I've never talked to Mr. Durham," Graham said. "I think he's a very capable, fair-minded prosecutor, but every time you look under one rock, you find something new. We've found in the last two or three days that the Russian sub-source [in the Steele dossier] was actually suspected by the FBI of being a Russian spy all the way back to 2009. They never told the FISA court that."

Ex-British intelligence agent Christopher Steele authored and compiled information for the anti-Trump dossier on behalf of Fusion GPS – the firm that was hired to conduct opposition research funded by the Democratic National Committee and the Hillary Clinton campaign through the law firm Perkins Coie.

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The dossier contains claims about alleged ties between President Trump and Russia that served as the basis for FISA warrants obtained against former Trump campaign aide Carter Page.

Fox News' Brooke Singman and Vandana Rambaran contributed to this report.