BOSTON (CN) — The Massachusetts Supreme Judicial Court approved some broad police searches of cell-phone location data Friday, but also placed limits on police activity to limit mass surveillance and intrusions against innocent people’s privacy.
The case arose from a string of six similar armed robberies in the Boston area. Police had no suspects, so they got a warrant for a “cell tower dump” to identify the phone numbers of everyone who had used a phone in the area of the six robberies at the time — ultimately yielding 50,951 unique phone numbers.
After police found a number that was present at many of the crimes, Jerron Perry was indicted in October 2019. Perry faces murder charges because someone died in one of the robberies.
A year ago, a lower court said the police acted properly, but the state’s high court agreed to review the ruling based on Perry’s complaint that the police were impermissibly gathering private data on tens of thousands of people who did nothing wrong.
In a 52-page opinion, the court said the police acted properly in this case, but only because there was a specific reason to believe that Perry used his phone during the crimes to contact a getaway driver.
Although cellphone data is a 21st century issue, the briefs went all the way back to Tudor England when police could be given a “general warrant” to rummage through anyone’s belongings, usually looking for “subversive” Catholic or Puritan literature. In the Colonial era, British officials were often given a similar right to forcibly enter people’s homes looking for untaxed goods.
The Founders wrote the Fourth Amendment in response, stating that warrants require probable cause and a specific description of what is being searched for.
Perry’s lawyers argued in their brief that what the state did here amounted to a general warrant with the goal of “obtaining a haystack in hopes of finding a needle.”
The ACLU filed an amicus brief arguing that cell tower data searches are an indiscriminate invasion of privacy. They are “inherently unreasonable because they constitute bulk surveillance [and] leave to the officers’ discretion how to manage the vast trove of private (but irrelevant) information that the government obtains,” the group claimed.
An organization called the Surveillance Technology Oversight Project told the court that the nature of cell towers “will radically skew the precision of cell tower data for low-income communities [and] likely accelerate surveillance and over-policing of marginalized and multi-marginalized communities.”
That’s because many minority group members live in cities where cell towers are more densely packed, said Brian Owsley, a professor at the University of North Texas Dallas College of Law, who has written several law review articles on cell tower searches.
The U.S. Supreme Court held in 2018 that many cellphone data searches require a warrant. In this case, the police did get a warrant, so the question was how far police can legitimately go with a warrant.
Most of the time, police already have a suspect and they want to use cell data to track that suspect’s movements. What makes this case different is that police were using cell data to find a suspect in the first place.
“The problem is that they’re fishing for a suspect,” Owsley said, and they will necessarily uncover lots of information about many innocent people during the search.
“Maybe the data will show that someone is having an affair,” he explained. “If you have enough data points you can see that someone is at the OB-GYN and then at a baby store or an abortion clinic. Or at a gay bar. The data show all kinds of intimate details for non-suspects.”
Laura Hecht-Felella, a civil rights and technology expert who published an essay on the issue, said the Supreme Court has established that “people maintain a reasonable expectation of privacy against prolonged, technologically aided police surveillance even if they are in public view.”
“There are obvious parallels between this kind of dragnet surveillance and the Framers’ concerns about general warrants,” added Hecht-Felella, a fellow at the Brennan Center for Justice at NYU School of Law. “The Fourth Amendment was created to prevent exactly this type of mass surveillance.”
The Massachusetts judges shared these concerns at oral argument, but in the end the unanimous court said the phone dragnet was OK because there was “particularized evidence that the perpetrator had used a cellular telephone during the commission of the offenses, or in the periods immediately before or thereafter.”
This was because Perry allegedly used a getaway driver who was stationed at some distance from the crimes and it was reasonable to assume that they communicated by phone.
However, a “tower dump” would not be allowed if the police merely said they thought the perpetrator had a phone because most people typically carry phones, Justice Frank Gaziano warned.
The court also specified that warrants for tower dumps must be approved by a judge, not just a magistrate, and the warrant must specify that data about innocent people caught up in the dragnet will be promptly destroyed and can’t be used by the police for any other purpose.
The New York Legislature is currently considering a bill to outlaw tower-dump searches altogether.
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