[JURIST] Loevy and Loevy [official website], a civil rights law firm, filed a federal lawsuit [complaint, PDF] Thursday challenging the use of a secret cellphone tracking system by the Chicago Police Department [official website]. The suit was filed on behalf of attorney Jerry Boyle, a volunteer for the National Lawyers Guild [advocacy website], who claims police intercepted information from his cellphone at a Black Lives Matter protest for Martin Luther King Jr. Day in 2015. Boyle claims that, as a result of the interception, his Fourth and First Amendment rights were violated. The tracking system in question is known as a “stingray.” Stingrays are devices which, by mimicking the function of a cell tower, can be used to determine a mobile phone’s location and intercept calls and text messages from both the target phone and other nearby devices.

Stringrays have received differing treatment. In November the US Court of Appeals for the Seventh Circuit ruled [opinion, PDF] against a criminal defendant challenging the use of a stingray by Wisconsin police to locate him without a warrant. The court concluded, “[a] person wanted on probable cause (and an arrest warrant) who is taken into custody in a public place, where he had no legitimate expectation of privacy, cannot complain about how the police learned his location.” In 2014 the Supreme Judicial Court of Massachusetts held [JURIST report] that law enforcement must obtain a warrant before using means such as stingrays to track a criminal suspects movements. In 2013 the New Jersey Supreme Court also ruled [JURIST report] that police must obtain warrants before tracking information from cell phone providers. As the dissent in the Wisconsin ruling notes, very little is known about stingrays and how they function. The dissent claims this is largely due to the government’s refusal to reveal any information about the device and has, at times, dismissed cases and withdrawn evidence rather than reveal any information. All past cases concerning the use of stingray have been in a criminal context. Boyle’s suit will be the first to approach stingray use through a civil claim.