Depending on the importance of the case, federal agents can potentially tap facial databases held by driver's-license registries, state criminal justice systems, the FBI, the State Department and the Defense Department, which has several million searchable faces, mostly Afghans and Iraqi men. Together these amount to an estimated 400 million facial images in government hands, though the rules on access to each database varies. (Often an individual is pictured in more than one database, or even more than once in a single one.)
Federal investigators searched several facial databases in the aftermath of the Boston Marathon bombing in April, officials said, speaking on the condition of anonymity to discuss an ongoing investigation. But the images were not clear enough to produce hits, even though both of the alleged bombers had driver's licenses in Massachusetts, a state that uses facial-recognition technology.
Yet as facial databases grow and video cameras become more prevalent and powerful, such searches will become more effective, experts say.
"More and more, what you're going to see is criminals and other people whose images were taken over the years are digitized, [and] put into these databases, and incidents like Boston will be easier to solve," said James Albers, senior vice president for government operations for MorphoTrust USA.
The Pinellas County Sheriff's Office says its facial-recognition unit conducts 5,000 searches a month and has assisted in nearly 1,000 arrests since 2004. A bulletin board in the office is lined with success stories: A teenage boy who was sending lewd messages to young girls through multiple Facebook accounts was identified, as was a suicide victim and an alleged bank robber — whose scowling image was captured by the branch's surveillance camera.
In another case, a man reported a stolen computer but then noticed that an online photo album he long had maintained was automatically uploading new snapshots of a couple he did not recognize. When the sheriff's office ran a search, the pictures matched faces in both the mug-shot and driver's-license databases. The couple soon fingered an acquaintance who was arrested for stealing the computer and then selling it to them.