Former Rep. Trey Gowdy said on Monday there is damning evidence out there for investigators to find as they examine the FBI's conduct in the early stages of the Trump-Russia investigation.

Top Republicans are talking up classified documents they believe will root out FBI misconduct in their use of an unverified dossier to obtain a Foreign Intelligence Surveillance Act warrant to wiretap Trump campaign adviser Carter Page. With Justice Department Inspector General Michael Horowitz in the final stages of a FISA abuse investigation, lawmakers have referred to him newly revealed information about the dossier's author.

Gowdy, now a Fox News contributor, was brought on Sean Hannity's show to discuss the development. Hannity asked if Gowdy was convinced there was fraud committed against the Foreign Intelligence Surveillance Court, noting how the FBI did not disclose dossier author Christopher Steele's anti-Trump bias and Democratic benefactors.

"I can tell you it is even worse than what you described," Gowdy replied. "It is what you described, in addition to the withholding of exculpatory information."

Gowdy said the FBI made no effort to corroborate the dossier until after it was used in the application and a renewal.

Republican investigators have sent out a flurry of letters in recent days requesting documents from top agency officials related to a meeting between Steele and Deputy Assistant Secretary of State Kathleen Kavalec on Oct. 11, 2016, 10 days before the first warrant application was submitted, and admitted he was encouraged by a client to get his research out before the 2016 election on Nov. 8, signaling a possible political motivation. The meeting was described in notes taken by Kavalec that were obtained by conservative group Citizens United through open-records litigation.

During a Fox News interview Sunday, Rep. John Ratcliffe, R-Texas, said the classified documents Republicans seek will lead to accountability with former CIA Director John Brennan, former FBI Director James Comey, and former Director of National Intelligence James Clapper.

Gowdy, the former chairman of the House Oversight Committee, said before he left Congress that he saw the relevant information shared with the Gang of Eight, including the FBI's own assessment of whether Steele was reliable.

Gowdy got even more specific when he made a plea: "To whoever is investigating this: Tell them to look for emails between Brennan and Comey in December 2016."

Both Comey and former FBI General Counsel James Baker have said they are confident the bureau did nothing wrong in obtaining the warrants, although Baker admitted the DOJ inspector general's FISA abuse investigation will find "mistakes."