Little-known surveillance tool raises concerns by judges, privacy activists
The investigations used a device known as a StingRay, which simulates a cellphone tower and enables agents to collect the serial numbers of individual cellphones and then locate them. Although law enforcement officials can employ StingRays and similar devices to locate suspects, privacy groups and some judges have raised concerns that the technology is so invasive — in some cases effectively penetrating the walls of homes — that its use should require a warrant.
The issues, judges and activists say, are twofold: whether federal agents are informing courts when seeking permission to monitor suspects, and whether they are providing enough evidence to justify the use of a tool that sweeps up data not only from a suspect’s wireless device but also from those of bystanders in the vicinity.
In Northern California, according to the newly disclosed documents, judges expressed concerns about the invasive...