“According to new Justice Department e-mails obtained by the American Civil Liberties Union (ACLU) of Northern California, and published on Wednesday, federal investigators have been routinely using ‘stingrays’ to catch bad guys,” Cyrus Farivar reports for Ars Technica.

“A stingray is a device that can create a false cellphone tower, and allows authorities to determine a particular mobile phone’s precise location. Stingrays aren’t new—law enforcement agencies nationwide are believed to have been using them for years,” Farivar reports. “But one e-mail in the new trove reveals something brand-new: that the Feds were not fully clear about the fact that they were specifically using stingrays (also known as ‘IMSI catchers’) when asking for permission to conduct electronic surveillance from federal magistrate judges.”

Farivar reports, “Groups like the ACLU are concerned that unsupervised use of such technology can inadvertently collect information of people who are not suspected of any crime, nor under investigation.”

Much more in the full article here.