The Maryland Court of Special Appeals held that the Baltimore police’s use of a cell site simulator used to locate and arrest a suspect violated his Fourth Amendment right against unreasonable searches.
According to the ACLU, Maryland is one of 23 states whose law enforcement agencies own cell site simulators. A simulator, often referred to as a StingRay or Hailstorm, locates cell phones by forcing mobile devices to repeatedly transmit their unique identifying electronic serial numbers. By measuring the signal strength of those transmissions, the simulator is able to pinpoint the exact location of the target cell phone. While cell site simulators have been used thousands of times by Baltimore police alone, Maryland’s state and local police must now obtain a valid search warrant in order to use such a device.
In its 72 page opinion, the court declared that people have an objectively reasonable expectation that their cell phones will not be used as real-time tracking tools by the government. It held that the use of a cell site simulator constitutes a search under the Fourth Amendment based upon two separate foundational principles underlying Fourth Amendment analysis of surveillance technology.
First, it concluded that surveillance conducted with electronic signals without trespass requires a determination as to whether the surveilled person had a legitimate and reasonable expectation of privacy. The court concluded, “[p]eople have a reasonable expectation that their cell phones will not be used as real-time tracking devices by law enforcement, and … that people have an objectively reasonable expectation of privacy in real-time cell phone location information.” It reasoned that cell phone users do not reasonably expect their movements to be recorded in a manner that enables the government to discover their private and personal habits and that the cell phone signals are not readily available in public view. The court also distinguished cell site simulators from information obtained from standard cell towers. Unlike cell towers, which merely await incoming signals, the Hailstorm is “an active device” that initiates contact with a cell phone and traces its response.
Second, it also determined that the use of surveillance technology without a warrant to obtain information about the contents of a home, not otherwise discernable without physical intrusion, constitutes an unlawful search. In this case, the defendant was inside a home when his location was tracked. But the court makes clear that the same concerns exist no matter where the defendant is located when subjected to a Hailstorm search, as the government cannot determine in advance where the target will go.
Finally, the court disposed of the State’s invocation of the third party doctrine, which states that individuals have no reasonable expectation of privacy in information that they voluntarily transmit to a third party. The State argued that because cell phones “come with ‘off’ switches,” when the defendant “chose to keep his cell phone on,” he “voluntarily shar[ed] the location of his cell phone with third parties” and no warrant was required. The court disagreed, asserting that the information was not transmitted to the third party service provider and then shared with law enforcement. Rather it was collected directly by the Hailstorm.
The court took particular issue with the lack of transparency in the State’s pen register/trap and trace application. The application failed to name or describe any cell site simulator, did not identify geographical limitations on the collection or explain how the collected information would be used, and neglected to disclose the potential collection of innocent third parties’ cell phone information. Due to these failures, the State “did not fully apprise the circuit court judge from whom [the order] was sought of the information that it would yield” and prevented the court “from exercising its fundamental duties under the Constitution.” The opinion noted that as a condition of purchasing the cell site simulators, the Baltimore City State’s Attorney entered into a nondisclosure agreement with the Federal Bureau of Investigation, which prevented the police department from making public its use of the equipment, whether in press releases, court documents, or judicial hearings. Accordingly, it announced that such an agreement “obstruct[ed] the court’s ability to make the necessary constitutional appraisal.”
A number of states’ legislators (including a proposed bill in Maryland) and courts are addressing the issue. The Seventh Circuit is currently examining a similar case, and a proposed federal bill would require all law enforcement agencies to obtain a warrant before employing cell site simulators. In fact, in September 2015, the Department of Justice announced a new policy requiring all federal law enforcement agencies to obtain a search warrant supported by probable cause before using cell site simulators.
