The bureau can draw from over 411 million photos spread across state and federal databases, including more than 173 million driver's license photos, as part of the new biometric effort. Those photos are regularly scanned by the FBI to match criminal suspects captured on video. But according to the GAO's investigation, the bureau failed to adequately test its database for accuracy, which critics worry could lead to suspects being falsely identified by the system.

"The nature and scope of this project is unprecedented."

The FBI's system became fully operational in April of 2015 after more than three years as a pilot program. Since the pilot began, FBI agents have run more than 36,000 scans, many of which were forwarded from state investigations. Presented with a single photo of the suspect, the system returns as many as 50 matching faces from the database, leaving it to the investigators to make the final identification. At the moment, only seven states have agreements to query the federal portion of the database — Arkansas, Florida, Maryland, Maine, Michigan, New Mexico, and Texas — but a number of other states are in negotiations with the bureau.