An attorney has filed a civil lawsuit against the City of Chicago and various members of the Chicago Police Department (CPD), claiming that their warrantless use of stingray devices on individuals attending a 2015 public protest was a violation of their constitutional rights.

In a filing with the U.S. District Court for the Northern District of Illinois, Eastern Division, attorney Jerry Boyle claims that the CPD used the devices to track him and countless others through their cell phone use during the Reclaim MLK Day rally on Jan. 15, 2015. Boyle is seeking a class action judgment with compensatory and punitive damages, as well as an injunction forbidding local authorities from using the technology further.

Police departments use stingrays, or cell site simulators, to impersonate cellular towers, essentially tricking a suspect's phone into transmitting data to the device's operator. The technology is controversial as it also collects information on bystanders within its range and is capable of eavesdropping on text messages and phone calls. Moreover, some law enforcement agencies employ the technology without a warrant, in many cases merely relying on a pen register orders.

Boyle stated in the complaint that he attended the political rally – held to call attention to issues such as racial discrimination and police brutality – to observe the CPD's treatment of protesters. According to his account, at roughly 8 p.m., “one or more defendant cell site operators used a cell site simulator to search the private cell phones of Mr. Boyle and nearby protesters, bystanders and Chicago residents.” The plaintiff asserts that the incident took that the defendants lacked a warrant or probable cause to search and seize data from these phones.

Boyle alleges that the actions of Chicago and its police department violated the First and Fourth Amendments of the Constitution, as they impeded protesters right to free speech and violated federal protections against unlawful search and seizure. Boyle has also accused the defendants of violating federal and state law.

Exactly how Boyle knew of the police stingwray action was not made clear in the court papers, but he said that the information will come out as the case the proceeds.

According to a report by Ars Technica, this may be the first-ever civil case in which an individuals has alleged an unconstitutional search stemming from stringray usage. “I'm not aware of any stingray case in a civil context,” said Brian Owsley, a University of North Texas law professor and former federal magistrate judge, in an interview with Ars.

In July 2016, Illinois Governor Bruce Rauner signed legislation, effective Jan. 1, 2017, that requires police to obtain a warrant before employing stingray devices and limiting the circumstances under which they can be used.

Boyle's civil action was filed just one day before the U.S. Department of Justice and U.S. Attorney's Office released a report detailing its investigation of excessive force accusations leveled against the CPD. According to the report, the department “engages in a pattern or practice of force in violation of the Constitution.”

A spokesperson at the CPD told SC Media that the department does not comment on pending litigation.