Warrantless Cell Phone Location Tracking

Document Date: January 15, 2010

The American Civil Liberties Union has been concerned for some time about some federal prosecutors’ practice of seeking court orders to track the location of people’s cell phones without showing probable cause. Applications for such court orders are generally filed under seal and, usually, the court’s response is also secret. The result is that the law governing when the government may secretly track a person’s cell phone is itself largely secret.

That is why the ACLU is now seeking to submit an amicus curiae brief before any magistrate judge considering a cell phone tracking application of any type. Below are sample briefs presenting our view that the government must show probable cause in such an application, and urging the court to publish any resulting decision on this issue.

This is a draft brief that we prepared opposing an application for real-time cell site location tracking on less than a showing of probable cause. See the brief >>

This is a brief filed in the Third Circuit opposing an application for historical cell site location data on less than a showing of probable cause. The ACLU served as amicus curiae in this case with the Electronic Frontier Foundation (EFF), ACLU-Foundation of Pennsylvania, Inc., and the Center for Democracy and Technology. See the brief >>

See also our lawsuit that we filed with EFF against the Department of Justice to obtain records related to cell phone location tracking.

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