In a strong affirmation of the privacy interests of cellphone users, the Massachusetts Supreme Judicial Court (SJC) ruled unanimously earlier this week that law enforcement agencies in the Commonwealth must obtain a warrant to access anything more than a minimal amount of the cell-site location information (CSLI) that telecommunications companies collect about their users. The Cyberlaw Clinic filed an amicus brief in Commonwealth v. Estabrook on behalf of the American Civil Liberties Union of Massachusetts (ACLUM) and the Electronic Frontier Foundation (EFF) in support of privacy protection for CSLI.
As explained in a previous blog post on this case:
Cellular service providers must know where their subscribers are at any given time to provide them with service. Providers therefore collect vast quantities of location information, tracking the movements of customers wherever they go. Last year, in Augustine, 467 Mass. 230 (2014), the Supreme Judicial Court ruled that, in general, the police must get a search warrant to obtain location information from a cellular service provider. The ruling left open the possibility, however, that the police might be able to obtain a “brief period” of “six hours or less” of location information without a warrant but, instead, with a court order that is considerably easier to obtain.
At issue in Estabrook was whether law enforcement could obtain two weeks of CSLI with a mere court order, and yet take advantage of the Augustine exception, since it would only use six hours of this data in prosecuting the defendant. In rejecting this proposition, the SJC agreed with the position advocated by amici that the government cannot remedy the constitutional violation caused by conducting an unlawful, warrantless search by promising after the fact to use only what it might have lawfully obtained under the “six-hour” exception.