The Federal Bureau of Investigation is piloting a facial-recognition surveillance project that will store millions of mug shots, bureau Director James Comey told lawmakers Wednesday.

"We’re piloting the use of mug shots, along with our fingerprint database, to see if we can find bad guys by matching pictures with mug shots," Comey told the House Judiciary Committee during an oversight hearing. Comey said the project is focused on a database of mug shots taken of those arrested. The director wavered, however, when asked if the database would store drivers' license pictures.

"I don’t think so. The Next Gen Identification, as I understand it, is about mug shots," Comey said. "I think there is some circumstances in which when states send us records, they’ll send us pictures of people who are getting special driving licenses to transport children or explosive materials or something—but as I understand it, those are not part of the searchable Next Generation Identification database."

The Electronic Frontier Foundation, under the Freedom of Information Act, obtained records from the bureau showing that the so-called Next Generation Identification database will have as many as 52 million images by next year and include pictures of innocent people.

In response to a question from Rep. Zoe Lofgren (D-CA), the director said he wasn't sure of the accuracy of the EFF's claims.

"I saw some of the same media, and that's what led me to ask my folks: so what’s the deal with this?" Comey said. "And the explanation to me was the pilot is mug shots. Because those are repeatable, we can count on the quality of them. And they’re tied to criminal conduct, clearly. And so there was not a plan and there is not at present where we are going to add other non-mug shot photos. But again, if I’ve got that wrong I'll fix it with you."

Regardless, the database is expected to flourish in numbers. There were more than 12 million arrests in 2012, according to the latest FBI figures available. That's one arrest every two seconds.

The FBI is piloting the program with a company called MorphoTrust. Lofgren said MorphoTrust has also produced a State Department facial recognition database holding some 244 million images.

"Will your Next Generation Identification system be capable of importing the State Department records or searching the State Department records?" she asked.

The director couldn't answer. “I don’t know," he said. "I have not heard of that as either a current capability or an intended capability. I’ll get back to you."

Listing image by EFF