Facial Recognition Technology: Federal Law Enforcement Agencies Should Better Assess Privacy and Other Risks, Report to Congressional Requesters [open pdf - 13MB]
From the Highlights: "Federal agencies that employ law enforcement officers can use facial recognition technology to assist criminal investigations, among other activities. For example, the technology can help identify an unknown individual in a photo or video surveillance. GAO [Government Accountability Office] was asked to review federal law enforcement use of facial recognition technology. This report examines the 1) ownership and use of facial recognition technology by federal agencies that employ law enforcement officers, 2) types of activities these agencies use the technology to support, and 3) the extent that these agencies track employee use of facial recognition technology owned by nonfederal entities."
Government Accountability Office: https://www.gao.gov/