Former South Carolina Rep. Trey Gowdy applauded the Justice Department inspector general for grilling the "seminal" witness in its investigation into alleged abuse of the Foreign Intelligence Surveillance Act.

It was revealed Tuesday that DOJ Inspector General Michael Horowitz's team conducted a two-day interview in London with British ex-spy Christopher Steele, the author of the unsubstantiated and salacious dossier attacking President Trump.

Gowdy said he was "pleasantly surprised" by the development during a Fox & Friends interview on Wednesday.

"The only way Michael Horowitz can issue the kind of report that he wants to issue, that we would benefit from, is to interview every single witness. I cannot imagine a more seminal witness than Christopher Steele," Gowdy said. "So, kudos to them for going to Europe and interviewing him because they certainly couldn’t make him come here."

Three attorneys from the DOJ inspector general’s team met with Steele in person in London in early June, during Trump’s state visit to the United Kingdom. Although Attorney General William Barr predicted that the inquiry would wrap up by June, investigators found Steele's information credible enough to warrant extending their investigation indefinitely.

Horowitz launched an investigation in March 2018 into whether the FBI and DOJ filing of four FISA applications and renewals beginning in October 2016 to surveil former Trump campaign adviser Carter Page was an abuse of the FISA process. The applications relied heavily upon the unverified dossier compiled by Steele, who was hired by Fusion GPS. The opposition research firm was hired by Marc Elias of the Perkins Coie law firm at the behest of the Clinton presidential campaign.

Gowdy, a former chairman of the House Oversight Committee, said he has not spoken to former colleagues or Horowitz for updates on the investigation, but he did offer some perspective.

"The good thing about Michael Horowitz is he's happy to talk to anyone about timing, but he's not going to talk about substance. And I’m not a member anymore, so I would not even ask him about timing," Gowdy said. "I've heard it's been delayed a little bit, in part because of the new witnesses that have come forward. And also in part, I mean think, Horowitz is having to read this report in a SCIF, in a secure room. A lot of the report is going to be classified. I think, look, we all wanted it yesterday, but I’m willing to postpone when I get it to have the most thorough accounting of what happened over that year-and-a-half time period as possible."

Gowdy was also asked who else he wants the inspector general to interview.

"I don’t know everyone that Horowitz has interviewed, but you’re going to have to hear with respect to that factual predicate in early 2016. You know, we repeatedly asked the bureau when did the investigation into the Trump campaign begin, they always said July of 2016, which is when [former FBI agent] Peter Strzok initiated it," Gowdy said. "I want to talk, I want to talk to the agent who was handling Steele. I want to talk to anyone who can shed light when the world’s premier, most powerful law enforcement agency decided to investigate a presidential campaign. Look, Horowitz was a prosecutor before he became IG. Really smart guy. There is nothing I can tell him he doesn’t already know. Go find everyone who knows anything. And then, write the most thorough, apolitical report you possibly can."