The pivotal role that cellphone records played in these two prominent New York murder trials this year highlights the surge in law enforcement’s use of increasingly sophisticated cellular tracking techniques to keep tabs on suspects before they are arrested and build criminal cases against them by mapping their past movements.
But cellphone tracking is raising concerns about civil liberties in a debate that pits public safety against privacy rights. Existing laws do not provide clear or uniform guidelines: Federal wiretap laws, outpaced by technological advances, do not explicitly cover the use of cellphone data to pinpoint a person’s location, and local court rulings vary widely across the country.
In one case that unsettled cellphone companies, a sheriff in Alabama told a carrier he needed to track a cellphone in an emergency involving a child — she turned out to be his teenage daughter, who was late returning from a date.
[…] The frequency and ease with which law enforcement agencies access cellphone data to track people is difficult to assess. Civil liberties groups recently obtained data from the Justice Department through a lawsuit showing that in some jurisdictions, including New Jersey and Florida, courts often allow federal prosecutors to track the location of cellphone users in real time without search warrants.
Investigators seeking warrants must provide a judge with probable cause that a crime has been committed. But investigators often obtain cell-tracking records under lower standards of judicial review — through subpoenas, which are granted routinely, or through an intermediate type of court order based on an argument that the information requested would be relevant to an investigation.