In the Northern District of California, federal prosecutors and and civil liberties advocates continue to debate over the government’s long time practice of obtaining cellphone location information with first obtaining a warrant.

Nathaniel Cousins, U.S. Magistrate Judge, challenged prosecutors last month to explain the reason why they should be able to have access to records without a showing of probable cause. Cousins also invited the federal public defender for the Northern District of California to weigh in on the topic. The American Civil Liberties Union as well as the Electronic Frontier Foundation entered the discussion at the end of July with an amicus brief, backing the federal public defender’s argument that prosecutors must display probable cause in order to obtain historical cell site records, which reveal the specific location of a mobile phone by showing which towers the device connects to.

Civil liberties advocates continue to oppose the government’s procedures in criminal investigations with renewed purpose in light of Riley v. California, a June U.S. Supreme Court decision stating that police officers may not search a suspect’s cellphone without first obtaining a warrant. Cell site information emerged as a heated topic following the U.S. Court of Appeals for the Eleventh Circuit’s decision which barred prosecutors in June from collecting the records without first showing probable cause.

However, federal prosecutors opposing this argue that they should not face such an obstacle to obtain information that mobile phone users share freely with their providers. They noted that cell phone service providers inform customers in their privacy policies that they would collect location information.