According to Boston Police Department records disclosed to the ACLU, the department has never obtained a search warrant to use highly controversial and invasive cell phone tracking technology, raising serious questions about the legality of the surveillance pursuant to the Fourth Amendment to the United States Constitution and Article Fourteen of the Massachusetts Declaration of Rights.

Cell site simulators—often referred to as Stingrays, the brand name of one popular model—track and monitor cell phone users by tricking phones into thinking they are communicating with cell phone company towers, when in fact they are sending sensitive personal information to law enforcement. This powerful surveillance device not only gathers data about the intended target, but can also sweep up information from countless bystanders who are monitored just because they were in the wrong place at the wrong time.

This kind of invasive search triggers protections under the Fourth Amendment, which controls how government agencies may conduct searches of people and their property. As a federal court in New York held earlier this month, “absent a search warrant, the Government may not turn a citizen’s cell phone into a tracking device.”

Given these facts, the Boston Police Department’s disclosures regarding its Stingray deployments raise serious concerns. In January 2016, the ACLU submitted a public records request asking the BPD to disclose how and when it uses its Stingray. The BPD’s response was as notable for what was missing as for what was included. Most troublingly, even though BPD has publicly claimed it requires its officers to get a warrant to conduct Stingray surveillance, the documents officials provided in response to our public records request show they have never once done so.

Instead, in each of the nine documented cases in which the department used a Stingray during a BPD investigation, they relied on an exception to the warrant requirement, known as “exigent circumstances,” or the “emergency exception.” Based on available information, it is impossible to evaluate the underlying circumstances of these cases. The BPD only provided three sparse incident reports, which are insufficient to show whether or not the emergency exception to the warrant requirement legitimately applied in each case. In the six other cases in which the department has admitted using a Stingray without a warrant, the BPD provided no official documentation that would allow the public to judge whether the emergency exemption was properly invoked.

But the emergency exception to the warrant requirement is meant to be just that—something that is used only in true emergencies, such as when human life is imminently endangered. In order to protect our constitutional rights, courts have interpreted the emergency exception very narrowly. But when it comes to Stingrays, for the BPD the exception seems to have become the rule.

The BPD’s apparent failure to seek warrants to use its Stingray raises serious Fourth Amendment concerns, as well as questions regarding notice and the opportunity to challenge the constitutionality of such surveillance. The public, the courts and criminal defendants have a right to know when and how this invasive technology is used, particularly when Stingray-derived information is used to build a criminal case against someone or locate someone for arrest.

To that end, the BPD should (1) adopt a clear, publicly available policy explicitly outlining a warrant requirement for Stingrays, (2) mandate detailed, publicly available records of each instance in which a Stingray is used in exigent circumstances, (3) publicly release, on a quarterly basis, a log of each time the Stingray is removed from a police station, and (4) expressly require notice to criminal defendants when officers use a Stingray to investigate or locate them.


Boston Globe: Police use of cellphone tracking devices raises questions
PrivacySOS: Boston Police records show the department has never gotten a warrant to use a stingray
ACLU of Massachusetts media release: Boston police documents reveal use of cell phone surveillance without a warrant


BPD January 2016 Partial Response
BPD Search Warrant Application Rule 334 (attached to January 2016 Partial Response)
BPD March 2016 Partial Response
BPD April 2016 Partial Response
BPD Incident Reports (attached to April 2016 Partial Response)