Judge Limits Searches Using Cellphone Data The government must obtain a warrant based on probable cause of criminal activity before directing a wireless provider to turn over records that show where customers used their cellphones, a federal judge ruled Wednesday, in the first opinion by a federal district court on the issue. Judge Terrence F. McVerry of the Western District of Pennsylvania rejected the government's argument that historical cellphone tower location data did not require probable cause. The ruling could begin to establish the standard for such requests, which industry lawyers say are routine as more people carry cellphones that reveal their locations. Around the country, magistrate judges, who handle matters such as search warrants, have expressed concern about the lack of guidance. In this case, which involved a government investigation of a drug trafficker, the judge affirmed a February ruling by U.S. Magistrate Judge Lisa Pupo Lenihan that whether the data sought was historical or real-time, it required a warrant. At issue was a government request for an order directing Sprint Spectrum to disclose historical cellphone data that included cell tower location information as well as call times and durations. Lenihan said the information sought, which she said could identify a subject's location to within about 200 feet, was "extraordinarily personal and potentially sensitive . . . (and) particularly vulnerable to abuse."....