Department of Justice Inspector General Michael Horowitz delivered a troubling picture of missteps taken during the FBI’s investigation into Trump campaign associates on Wednesday, saying his findings should not be viewed as a vindication of the bureau.

Horowitz, testifying for more than five hours before the Senate Judiciary Committee, outlined the findings of his 20-month investigation into the bureau’s probe, saying he found “basic, fundamental and serious errors” as part of the FBI’s process.

“We are deeply concerned that so many basic and fundamental errors were made by three separate, hand-picked investigative teams, on one of the most sensitive FBI investigations, after the matter had been briefed to the highest levels within the FBI,” Horowitz told lawmakers.

Horowitz’s testimony came two days after he released his 434-page report on his findings. Horowitz’s report found that there was no evidence of political bias in the decision to open the investigation and that the bureau had an “authorized purpose” for the probe.

But Horowitz also found 17 “significant inaccuracies and omissions” throughout the FBI’s investigation. The bulk of his testimony on Wednesday was focused on issues he found within the probe, particularly in the follow up requests for Foreign Intelligence Surveillance Act (FISA) warrants tied to Trump campaign aide Carter Page.

Pressed by Sen. Patrick Leahy (D-Vt.) that he found “no evidence that the investigation was motivated by anti-Trump or political bias,” Horowitz stopped short.

“We found no evidence that the initiation of the investigation was motivated by political bias. It gets murkier — the question gets more challenging, senator — when you get to the FISA. When you get to the attorney's actions, for example, in connection with that FISA,” Horowitz added.

Horowitz appeared to be referring to Kevin Clinesmith, a front-line lawyer. Clinesmith, according to the inspector general report, altered an email related to the warrant renewal application.

Horowitz also declined to say if he thought the FISA warrant applications on Page would have been accepted if the court knew all of the information that he found during his investigation. He also specifically said he personally would not have submitted the subsequent FISA warrant applications as they were originally drafted and submitted by the FBI.

“It had no business going in,” Horowitz said.

Pressed by Senate Judiciary Committee Chairman Lindsey Graham (R-S.C.) if the FBI was lying to the FISA court during the warrant application process, Horowitz said “it was misleading to the court.”

Pressed later by Graham if the handling of the subsequent FISA warrant applications was “off-the-charts bad,” Horowitz replied: “It’s pretty bad.”

Horowitz also specifically broke with former FBI Director James Comey, who wrote in The Washington Post that the report disproved declarations from Trump and his allies that the FBI “spied” on the Trump campaign and engaged in wrongdoing.