The U.S. Court of Appeals for the Fifth Circuit ruled in July that the police do not need a warrant to access mobile phone subscribers cell phone tower data. The Fifth Circuit, which has the final word on matters of Federal law in Texas, held that warrantless access to such information by police is not a violation of the Fourth Amendment’s prohibition against unreasonable search and seizure.
Instead, according the the Fifth Circuit, the information is merely a business record created and maintained by the private cell companies. Further, the Government is not involved in the creation or storage or the accumulated data, and for a variety of reasons, the Court held that an individual has no expectation of privacy in the data.
What does this mean? As a practical matter, the phone in your pocket or purse is a de facto tracking device. If you use a cell phone you may be tracked to a relatively small area by use of the cell phone tower data. This data is now accessible without a warrant.