https://www.recode.net/2017/8/15/16151676/apple-facebook-google-snap-supreme-court-privacy-carpenter-united-states

A collection of the country’s largest tech companies — including Apple, Facebook, Google, Microsoft and Snap — urged the Supreme Court this week to set new limits on the ways law enforcement can obtain a suspect’s smartphone location data.

The case before the nation’s justices is Carpenter vs. United States, and it stems from a 2011 investigation into a series of robberies in Detroit. As part of the probe, law enforcement officials obtained information from nearby cell towers to determine the whereabouts of one of the suspects, Timothy Carpenter, without first obtaining a warrant.