Lawmakers on Tuesday grilled federal law enforcement officials on the integrity and legality of the government’s facial recognition programs, and criticized the nearly nonexistent oversight Congress has over those programs.

During a hearing, members of the House Oversight Committee questioned witnesses on the steps being taken to ensure the facial recognition tools used by their agencies aren’t infringing on individuals’ privacy and civil liberties. By and large, lawmakers on both sides of the aisle seemed unsatisfied with their answers.

And while the committee criticized law enforcement’s facial recognition efforts en masse, much of their attention focused on the FBI’s use of the tech.

Lawmakers criticized Kimberly Del Greco, deputy assistant director of the FBI’s Criminal Justice Information Services division, over the bureau’s failure to correct multiple flaws in the way it evaluates its primary facial recognition tool. In 2016, the Government Accountability Office issued six recommendations to ensure the tech, known as the Next Generation Identification-Interstate Photo System, meets federal privacy and accuracy standards. As of Tuesday, auditors said the bureau had only put one of the fixes in place.

Gretta Goodwin, director of GAO’s Homeland Security and Justice office, found the FBI never published key privacy documents related to the NGI-IPS. The bureau also failed to test the accuracy of both its own facial recognition system and the software provided by its various partners, which include the State and Defense departments, and some 21 state governments.

According to Goodwin, the NGI-IPS database contains some 36 million criminal mugshots but combined with the other image databases provided by its partners, the FBI can run facial recognition software against some 640 million total photos.

The FBI disagrees with GAO’s assessment of its privacy disclosure requirements, Del Greco said, and has since conducted accuracy tests of its own system with the help of the National Institute of Standards and Technology. Goodwin said GAO has yet to see the results of the test.

“It will be important that [the Justice Department] takes steps to ensure the transparency of the systems so that the public is kept informed about how personal information is being used and protected, that the implementation of the technology protects individuals privacy and that the technology and systems used are accurate and are being used appropriately,” Goodwin said.

If the FBI implemented all five remaining recommendations, she added, it “would actually go a long way in … addressing some of the concerns.”

Lawmakers also called for more oversight of the Transportation Security Administration’s budding facial recognition program, which is testing the tech to identify travelers before they board flights and track them through the baggage claim process. Customs and Border Protection is also well underway with its own efforts to use facial recognition to monitor people entering and leaving the country.

During a hearing last month, committee members from both political parties called for Congress to place more stringent standards on law enforcement’s use of facial recognition software. On Tuesday, they echoed the same sentiments.

“Of all the issues that we’ve been dealing with, this will probably receive the most intense scrutiny of them all,” Chairman Elijah Cummings said in his closing remarks. “We want to get it right, it’s just that important.”

FBI Denies Amazon Facial Recognition Pilot

During the hearing, Del Greco also told Congress the FBI was not testing Amazon’s controversial facial recognition software—Amazon Rekognition—for use in federal investigations. But multiple news outlets, including Nextgov, have reported the bureau was experimenting with Amazon’s tech as recently as last year.

The company’s software came under sharp criticism after it mismatched 28 members of Congress to criminal mugshots, with mistakes more common among people of color.

“No, there is not [a pilot program],” Del Greco said when Rep. Rashida Tlaib, D-Mich, questioned her about the bureau’s work with Amazon. “To the best of my knowledge, and I verified before I came today, the FBI does not have a contract with Amazon for their Rekognition software.”

At Amazon Web Services’ conference in November, former FBI Deputy Assistant Director for Counterterrorism Christine Halvorsen discussed using Rekognition to sift through troves of video surveillance footage agents collect during counterterrorism investigations. According to Halvorsen, the pilot launched after the mass shooting in Las Vegas tested the limits of the bureau’s technological capabilities.

“We had agents and analysts, eight per shift, working 24/7 for three weeks going through the video footage of everywhere [Stephen] Paddock was the month leading up to him coming and doing the shooting,” Halvorsen said on stage. By comparison, she said, it would’ve taken Rekognition just 24 hours to sort through the same mountain of footage.

When asked about the existence of the program by Nextgov, the FBI declined to provide additional details on Del Greco’s testimony. Amazon also declined to comment. According to Halvorsen’s LinkedIn profile, she left the FBI in April to join AWS as a strategic account executive.

Cummings requested the FBI provide documentation that it was not currently using Amazon’s facial recognition software, and Del Greco agreed to do so.