Former U.S. Attorney Joe diGenova revealed the source of his insider information about the Justice Department inspector general's incoming report on alleged Foreign Intelligence Surveillance Act abuses.

Earlier this week, diGenova said Inspector General Michael Horowitz has determined all four FISA warrants against one-time Trump campaign aide Carter Page were illegally obtained.

He told the Washington Examiner's Examining Politics podcast on Thursday how he heard about it.

"It's very clear that he was also in the FISA warrants, all four of which were illegal. We know as a result of — the reports are being circulated inside and outside of the department for comment by interested parties. So we know that all four FISA warrants were illegal," he told host Larry O'Connor.

The investigation into the DOJ's and the FBI's conduct has wrapped up, according to a report last week. After a declassification period, the report could be released sometime in September. The contents of the report have not been confirmed.

Attorney General William Barr, who is overseeing U.S. Attorney John Durham's investigation into the origins of the Russia investigation, said he is working closely with Horowitz, and they will take up any criminal referrals Horowitz might make.

DiGenova said if he were attorney general, any officials involved in obtaining the Page FISA warrants who are still in the department would be "gone." He singled out Dana Boente, who is the general counsel now under FBI Director Christopher Wray. The April 2017 FISA renewal was approved by Boente and former FBI Director James Comey, who was harshly criticized in a separate report released Thursday.

DiGenova also discussed the two people he wants to hear from after the FISA report is released. He said he wants to know what the presiding judge of the 11-member FISA Court, Rosemary Collyer, will do to the people who "lied" to the court. And diGenova said he wants to hear from Supreme Court Chief Justice John Roberts, who makes appointments to the court and supervises it.

"He had no problem criticizing the president of the United States for making comments about the political leanings of some judges on the 9th Circuit," DiGenova said of Roberts. "Well, Mr. Chief Justice, get off your tush and tell us what you think about this disgraceful conduct in your court — the FISA Court."

Sen. Lindsey Graham, the chairman of the Judiciary Committee, said he will ask Roberts to investigate possible abuse of the Foreign Intelligence Surveillance Court during the 2016 election.