But - no surprise - much of the hearing instead focused on the highly anticipated Mueller report.
Barr also reminded lawmakers that the regulation he is under does not require him to release the report at all.
With a tinge of sarcasm in her voice, Lowey called it "extraordinary" that Barr was able to "evaluate hundreds of pages of evidence, legal documents, and findings based on a 22-month-long inquiry and make definitive legal conclusions in less than 48 hours".
"I could envision a situation where under appropriate safeguards, that information would be shared", Barr said.
RYAN LUCAS, BYLINE: Hi there. "And so I think that from my standpoint, within a week I will be in a position to release the report to the public".
At the same time, Horowitz's office confirmed it would "review information that was known to the DOJ and the Federal Bureau of Investigation at the time the applications were filed from or about an alleged Federal Bureau of Investigation confidential source" and "review the DOJ's and FBI's relationship and communications with the alleged source as they relate to the (Foreign Intelligence Surveillance Court) applications". He later argued that Barr had "unlimited discretion" to redact information outside of 6 (e) information.
Barr also suggested that the report would not be filled with pages of redactions.
Facing the intensifying concerns from Democrats that he may have whitewashed Mr Mueller's findings, Barr has twice moved to defend, or at least explain, his handling of the process since receiving the special counsel's report.
LUCAS: Well - and that's not all. They'll see exactly what Barr wants them to see.
That's what Barr is telling Congress during his testimony before a Senate subcommittee hearing.
A case filed a year ago in the Northern District of Texas claimed that in eliminating the tax penalty for failure to have health insurance, the entirety of the ACA is unconstitutional.
The host of the Fox News program, Maria Bartiromo, told Nunes that he "ought to be taking a victory lap here" after Barr's memo said there was no evidence of Russian collusion.
CHANG: All right. So this redacted report is heading our way very soon.
The attorney general said he has not received the criminal investigation referrals from Rep. Devin Nunes (R-Calif.) that the lawmaker mentioned earlier in the week.
Six leading Democrats, however, say they will fight the redactions.
LUCAS: Well, remember. Barr said that he wants to be as transparent as possible consistent with the law.
He asks for help in his effort to let the American people see the report and decide for themselves. They can draw their own conclusions, make their own judgments. As many as 13 requests to foreign governments for evidence were also made as part of the massive investigation.
It all seems conclusive enough, except for one critical aspect: we don't have the full report.
"That's what got everyone outraged at what FBI Director Comey did in the case of Hillary Clinton", Barr said. Barr said Mueller was given the opportunity to review that letter but declined to do so.
"Do you think it's likely we are going to prevail?"
He also disclosed that the Justice Department's internal watchdog, Inspector General Michael Horowitz, is expected to conclude an investigation into its counter-intelligence investigation into Russia's interference in the 2016 campaign and any connections between Moscow and Trump associates. We've talked about it a lot, about their allegations.
"Generally, grand juries are to investigate crimes and a prosecutor's role at the end of the day is binary", Barr said.
CHANG: OK. That's NPR's Ryan Lucas.