US government intelligence and police agencies use a variety of tools to keep a close eye on American citizens. While the NSA concentrates on digital voice and digital communications, local sheriff and police departments are often in charge of visual technologies, such as cameras. This information is often shared with regional intelligence services.
The use of surveillance technologies is often illegal or falls within a gray area of the law. Court decisions protecting privacy have often been technology-specific, which allows government agencies to circumvent them as new technological surveillance tools are developed.
The following are some of the surveillance technologies law enforcement agencies are known to use:
License Plate Readers (LPR)
These are cameras mounted on police or other vehicles or at static locations, which automatically photograph any license plate that falls within its field of view, as well as the car and area surrounding it. The photographs are time and location stamped, and may be kept indefinitely.
These cameras are usually at fixed locations, often in public property, and continuously transmit and/or record anything that falls within their field of view. Newer camera models come with hidden microphones.