“No,” Barr replied. “That is one of the areas that I am reviewing. I’m concerned about it. And I don’t think it’s entirely speculative.”

The review is part of an ongoing DOJ look into the origins of the Trump-Russia probe, which started after FBI officials noticed odd contacts between Kremlin-linked individuals and Trump campaign aides. Barr on Wednesday said his agency is also looking at steps the bureau took to monitor Trump’s campaign team during the presidential race. And he suggested that there may have been more to the FBI’s counterintelligence 2016 investigation into the Trump campaign that has not been previously disclosed.

The Justice Department declined to comment on the investigation beyond Barr’s testimony.

Barr is conducting the review in parallel with the Justice Department’s inspector general, Michael Horowitz, who has been examining the FBI’s efforts to surveil a one-time Trump campaign adviser, Carter Page. The application to monitor Page was based in part on information from Christopher Steele, the former MI6 agent who authored the bombshell dossier and served as a confidential source for the bureau.

Barr indicated he thought there had been some mismanagement in the early days of the Russia probe.

“To the extent that there was any overreach, I believe it was some — a few people in the upper echelons of the bureau and perhaps in the department,” Barr said. “But those people are no longer there, and I’m working closely with [FBI Director] Chris Wray, who I think has done a superb job at the bureau. We’re working together on trying to reconstruct exactly what went down.”

Barr’s prior comments about the Russia probe’s origins will likely weigh down whatever conclusions come out of his review.

The attorney general drew sharp criticism earlier this month when he said, “I think spying did occur” by the FBI on the Trump campaign in 2016. He added that he wasn’t necessarily suggesting that that spying was not proper, and that he had “no specific evidence” of misconduct. But Barr still said he would “explore” that question.

Barr’s critics claimed that “spying” is a loaded term, however, especially after Trump deployed the term to discredit the Russia investigation’s origins. They noted that the bureau received a lawful warrant from the Foreign Intelligence Surveillance Court to monitor Page. And the said the bureau’s early use of a confidential informant— Cambridge University professor Stefan Halper — was typical of counterintelligence investigations.

Barr defended his “spying” comment on Wednesday.

“I don’t think [spying] has a pejorative connotation at all,” Barr told Sen. Sheldon Whitehouse (D-R.I.). “Spying is a good English word that, in fact, doesn’t have synonyms, because it is the broadest word, incorporating all forms of covert intelligence collection. I’m not going to back off the word spying.”

Barr later offered more hints of what he was investigating.

“Many people seem to assume that the only intelligence collection that occurred was a single confidential informant and a FISA warrant,” Barr told Sen. Mike Lee (R-Utah) at Wednesday’s Senate Judiciary Committee hearing. “I would like to find out whether that is, in fact, true. It strikes me as a fairly anemic effort if that was the counterintelligence effort designed to stop the threat as it’s being represented.”

The special counsel’s final report detailed the Trump campaign’s many interactions with Russians in 2016 and determined that the evidence was not enough to establish that a criminal conspiracy had occurred.

But the report did not address the FBI’s counterintelligence findings, which Mueller says he handed off to the bureau throughout the course of his investigation. Nor did it shed any new light on what steps the FBI took in 2016 and beyond to determine whether Russia had every compromised Trump or members of his campaign, which Steele’s dossier alleged occurred in the years prior to the 2016 election.

Halper is not the only FBI source on Barr’s radar. Steele, the former British intelligence officer, has been an FBI source for nearly a decade. While he began providing the FBI with information about Trump’s alleged ties to Russia in 2016, his relationship with the bureau began in 2010 when he delivered them information about corruption within the international soccer league FIFA.

Steele specialized in Russia at MI6, where he worked for more than two decades, and ran the agency’s Russia desk from 2006-2009. But Barr suggested on Wednesday that Steele may have been duped by Russians feeding him disinformation.

Steele’s defenders have noted, however, that the information used from his dossier to justify monitoring Page has essentially held up.

According to Steele’s sources, Page met with high-level Russian officials while in Moscow in July 2016, including the CEO of Russia’s state-owned oil giant Rosneft. Page initially denied the claim, but later acknowledged under oath to meeting with “senior members of the presidential administration” during the trip, as well as with the head of investor relations at Rosneft. Page had originally claimed only that he went to Moscow to give the commencement address at the New Economic School.

Former FBI officials also told the DOJ inspector general that surveillance warrant applications sometimes include information that is not wholly verified. In those instances, they said, the reliability of the source of the information is disclosed to the court. The FBI did that regarding Steele in its surveillance application for Page.