Trump dossier author Christopher Steele will likely be interviewed by U.S. Attorney John Durham and will show the FBI lied to Congress, attorney Joe diGenova said on Tuesday.

A Sunday Times report said the British ex-spy agreed to talk with U.S. officials, if certain preconditions were met, and strongly suggested it was a deal with Justice Department Inspector General Michael Horowitz, who is conducting an investigation into alleged Foreign Intelligence Surveillance Act abuses.

But diGenova, a former U.S. attorney for the District of Columbia, insisted that Durham, not Horowitz, would be the one to talk to Steele.

"He's [Steele] obviously made a strategic decision because he's going to be interviewed by John Durham," diGenova said on Fox News. "It's not the inspector general from the Department of Justice who's going to talk to him because he doesn't have any reason to talk to Mr. Horowitz. He's going to talk to John Durham and his people. So there's obviously some sort of deal that has been worked out. This is great news."

Durham, a U.S. attorney from Connecticut, has been tasked by Attorney General William Barr to review the origins of the FBI's Russia investigation.

The report from British media said Steele is only willing to talk about his relationship with the FBI, for whom he was a confidential source, and wants the United States to get permission from the United Kingdom government first. The report came out as President Trump was in the country for a state visit.

Despite his certainty that Durham struck the agreement with Steele, diGenova said, "I can't believe that Durham would agree to such limitations."

"But this is what's important," diGenova continued. "He has to tell the truth to Durham because even though his testimony will be given overseas, he can be indicted in the United States if he lies to Durham. So I assume he's going to tell the truth because this is the big, this is the big casino now. And what he is going to prove is that the FBI lied in the FISA warrants and they lied to Congress and they lie to everybody about what they knew about Steele's behavior. ... The walls are beginning to close in on the FBI fraudsters."

Steele’s dossier, which was packed with unverified claims about Trump's ties to Russia, formed a key part of the FBI's Foreign Intelligence Surveillance Act applications that were used to justify surveillance warrants against former Trump campaign adviser Carter Page — a key point of concern among GOP investigators. Steele was working for Fusion GPS, which received funding through the Perkins Coie law firm from the Hillary Clinton campaign and the Democratic National Committee. Steele's Democratic benefactors were not revealed to the Foreign Intelligence Surveillance Court.

Former FBI top officials have defended their conduct, despite admitting there were unreliable claims in the anti-Trump research, and Steele himself has acknowledged having questionable sources.

DiGenova said Durham wants to talk to Steele because of "a criminal conspiracy" led by senior FBI officials.

DiGenova served as an independent counsel in the 1990s for a case on former President Bill Clinton's passport before he was elected. Last year, it was announced diGenova and his wife Victoria Toensing were joining Trump's legal team for the federal Russia investigation, but that plan was nixed within days.

He was highly critical of special counsel Robert Mueller's Russia investigation, claiming that Trump had been "framed" by the Justice Department and the FBI, and recently said Horowitz determined that the three Foreign Intelligence Surveillance Act extensions against Page were illegally obtained and was on the brink of finding the first Foreign Intelligence Surveillance Act was completely illegal.