; and (B) does not include any officer, employee, or contractor of a State department of motor vehicles. (8) Law enforcement agency The term law enforcement agency means any agency of the United States authorized to engage in or supervise the prevention, detection, investigation, or prosecution of any violation of civil or criminal law. (9) Probe image The term probe image means an image of a person that is searched against a database of known, identified persons or an unsolved photo file. (10) Prosecutor The term prosecutor means the principal prosecuting attorney of a State or any political subdivision thereof and any attorney for the Government (as such term is defined for the purposes of the Federal Rules of Criminal Procedure). (11) Operational testing The term operational testing means testing that evaluates a complete facial recognition system as it is used in the field, including measuring false positive and false negative error rates for field uses of the system on operational or operationally representative data and under the environmental conditions and technical product settings and configurations typically used, as well as assessing the variability of system use by different users. (12) Reference photo database The term reference photo database means a database populated with photos of individuals that have been identified, including databases composed of driver’s licenses, passports, or other documents made or issued by or under the authority of the United States Government, a State, a political subdivision thereof, databases operated by third parties, and arrest photo databases. (13) State The term State means each State of the United States, the District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, American Samoa, Guam, and the Northern Mariana Islands. I Use of facial recognition by Law Enforcement 101. Facial recognition (a) Reference photo databases (1) In general An investigative or law enforcement officer may only use or request facial recognition in conjunction with a