patrick.net

A number of police departments in California have been using controversial "StingRay" type of cellular interception devices for at least six years, with little or no disclosure, according to documents obtained by Sacramento's News10.

StingRays belong to a class of device made by Florida-based Harris Corporation that imitates part of the cellular infrastructure, causing nearby phones to connect to it. Some devices can even intercept calls and texts, though the documents don't indicate police used them for this purpose.

http://www.nbcnews.com/tech/security/stingray-records-show-secret-cellphone-surveillance-calif-cops-n52181

Stingrays can track users as they move around with their phones, with a level of accuracy that allows for tracking even inside buildings, according to the ACLU. Because they take in data from every phone in the area, instead of limiting the surveillance to actual suspects, the devices are constitutionally suspect, Lye wrote.

http://www.pcworld.com/article/2108320/california-police-criticized-for-stingray-cellphone-trackers.html