When the U.S. Attorney's Office in San Francisco applied for an order to obtain historical cell site records, federal magistrate Judge Nathanael Cousins wondered why the government did not believe it needed to apply for a search warrant to get this detailed location information of which cell phone towers a particular phone connects to. After the government explained why it did not believe it needed a search warrant, Judge Cousins invited the San Francisco Federal Defender to file a response.
EFF filed an amicus brief in support of the Federal Defender's argument that the government needed to use a search warrant to obtain historical cell site data. Our amicus brief argues there is a growing societal recognition that it is reasonable to expect privacy in cell phone data that reveals a person's location, as reflected by a growing number of state courts and legislatures requiring law enforcement use a search warrant to obtain this sensitive information. Our amicus brief also notes the California constitution specifically treats telephone records as private.