The Justice Department’s watchdog doesn’t trust the explanations given by FBI lawyers and agents for their glaring missteps and deceptions during the Foreign Intelligence Surveillance Act investigation into Carter Page.

Horowitz repeatedly made his dissatisfaction with the FBI known during a Wednesday hearing in front of the Senate Homeland Security and Government Affairs Committee.

Democratic Sen. Gary Peters of Michigan asked Horowitz if he concluded political bias played no role in the conduct of the FISA investigation into the former Trump campaign associate, and the inspector general said that wasn't something he would say because the bureau had committed too many mistakes and their explanations weren’t believable. Horowitz couldn’t decide whether the FBI’s improper actions were due to incompetence or if they were done purposely.

“As to the failures that occurred, we didn’t find any of the explanations particularly satisfactory — in fact, unsatisfactory across the board,” Horowitz said. “In the absence of satisfactory answers, I can’t tell you as I sit here whether it was gross incompetence. And I think with the volume of errors, I think you could make an argument that that would be a hard sell as to gross incompetence, to intentional, or somewhere in between, and what the motivations were.”

He “can think of plenty of motivations,” he said, but didn’t have “hard evidence” to prove it.

In his report, Horowitz said agents and supervisors told him “they either did not know or recall why the information was not shared” with DOJ leadership and with the FISA court, with bureau employees claiming “the failure to do so may have been an oversight, that they did not recognize at the time the relevance of the information to the FISA application, or that they did not believe the missing information to be significant.”

Horowitz said the failures were in fundamental parts of the process and that FBI agents ignored basic rules about making sure information was accurate and updating the court when they learned more.

"These were basic fundamental errors, and it’s hard to figure out what the rationale is, so we’re not sure what the motivation is,” he said.

Horowitz concluded that the FBI’s investigation was flawed and criticized the DOJ and the FBI for 17 “significant errors and omissions” related to secret surveillance court filings targeting Page, which relied on allegations contained within British ex-spy Christopher Steele’s dossier. The FISA court harshly critiqued the bureau, as well.

Republican Sen. Josh Hawley of Missouri listed a series of missteps by bureau agents and lawyers, including doctoring an email.

“These individuals deliberately and knowingly misled the FISA court. I mean, that’s a nice way of putting it. Basically, they lied to the FISA court to get an electronic surveillance warrant of an American citizen,” Hawley said. “Why would so many people do that?”

Horowitz replied that there were so many errors, his team couldn't reach a conclusion on their motivation.

“It certainly wasn’t the reasons that were offered to you,” Hawley said. Horowitz agreed.

Hawley also asked Horowitz if he found “that political bias did not affect any part of the Page investigation — any part of Crossfire Hurricane — is that what you concluded?”

Horowitz stopped short, however, of pointing to political bias.

"We have been very careful in the connection with the FISAs — for the reasons you mentioned — to not reach that conclusion," he said, because "in part, as we talked about earlier, the alteration of the email, the text messages associated with the individual who did that, and our inability to explain or understand, to get good explanations so that we could understand why this all happened.”

Under questioning from Republican Sen. Ron Johnson of Wisconsin, Horowitz drew a distinction between the investigation’s launch and the troublesome investigative steps during it, concluding its opening was justifiable and that Bill Priestap, the assistant director of the FBI Counterintelligence Division who opened the inquiry, was not motivated by political bias.