The FBI's facial recognition database
The FBI is rolling out an advanced $1 billion biometric system: Next Generation Identification (NGI), a nationwide database of mugshots, iris scans, DNA records, voice samples, and other biometrics. NGI's facial recognition systems can find a single face from a pool of 1.6 million mugshots and passport photos with 92% accuracy in less than 1.2 seconds -- even using photos in which the subject isn't looking at the camera.
The NGI pilot has used mugshots and driver's licenses of known criminals -- which would have been useless to stop the 9/11 hijackers with their clean records. But the NGI database won't stop at mug shots: agents could also upload a person of interest's picture and have NGI's cameras keep a lookout.