The intricate surveillance equipment used by the federal government to track and store the cellphone data of millions of people and to monitor terrorism suspects is making its way to Main Street.

Police departments across the nation have been trying to conceal their use of cellphone tracking equipment from local courts because of nondisclosure agreements that allow the departments to use the devices on loan – as long as they promise the manufacturer they will keep it a secret.

The devices, manufactured by the Florida-based Harris Corporation, are commonly used at the federal level, but are also proliferating across local and state police departments. The technology has been purchased under various names, including StingRay, HailStorm, Harpoon, AmberJack, KingFish and RayFish, and mimics a cellphone tower.

When cellphones connect to the device, it can record the phone’s unique information and traffic data, as well as its location. The devices can triangulate the position of a particular cellphone in relation to its antenna and other towers in the area with greater accuracy than would be possible from a network provider’s permanent tower location.

The devices are used to gather information about both specific individuals and large groups (including people involved in political dissent). They also sweep […]