Law enforcement's secretive and often-times warrantless use of the cellphone tracking device known as StingRay is receiving fresh scrutiny this week following an investigation into the Baltimore Police Department's widespread use of the device in crimes both large and small.
The controversial devices mimic cellphone towers, pinging nearby phones and allowing police to locate phones within a vicinity and obtain their data, and are used by both the federal government and more than 50 police departments across the country, according to the American Civil Liberties Union (ACLU).
An investigation by USA Today found that Baltimore police have used the device in 837 criminal cases, including serious crimes such as homicide and shooting cases, as well as petty crime cases involving credit card theft and harassing text messages.
Most significantly, however, was not how often the devices were used but how infrequently their use was made known to prosecutors, judges, and defense attorneys as the cases made their ways through court. When officers did seek permission from the courts, not through warrants but through "pen register" orders, USA Today found that police officers in Baltimore described the devices as "advanced directional finding equipment" or "sophisticated electronic equipment" when seeking court permission for their use.
"I am astounded at the extent to which police have been so aggressively using this technology, how long they've been using it and the extent to which they have gone to create ruses to shield that use," Stephen Mercer, the chief of forensics for Maryland's public defenders, told the paper.
Maryland, like most of the rest of the country, has no laws requiring police to get warrants for StingRay use.
A case in Washington state last year, in which the Tacoma News Tribune found that judges had no idea they were signing off on StingRay use, led the state legislature to pass a law this May requiring a greater amount of clarity and detail in any such warrants in the future. It's the first such law in the country.
'There's no way to surgically use StingRay. The only way it works is like a shotgun shooting in all directions'
The federal government came under fire in 2014 for StingRay use, leading the Senate Judiciary Committee to call on the Department of Justice (DOJ) to explain and defend the practice. The DOJ ultimately decided to voluntarily change its own Stingray policies, requiring a warrant for future use, though it added many exceptions into the new policy.
"The million dollar question is are the police getting search warrants, and the reason that's important is because a warrant requires probable cause. Those are the orders the Fourth Amendment requires," Christopher Soghoian, principal technologist at the ACLU, told VICE News.
Whether or not the departments are receiving warrants for StingRay use in individual criminal cases, there are almost always other citizens whose phones and data will be swept up in its use, Sohoian explained. The devices work by pinging all cell phones in a large geographic area.
"There's no way to surgically use StingRay. The only way it works is like a shotgun shooting in all directions," he said. "So the second concern is that this device, and many law enforcement agencies don't tell the courts or defense lawyers when using them, short-circuits the democratic process and raises significant concern about a fair trial."
Adina Schwartz, a criminal justice and law expert at John Jay College of Criminal Justice, said that StingRay use constitutes "real bulk collection" of private data. She cited ways in which police departments argue that it's not an invasion of privacy, including a provision of the Fourth Amendment that holds that information you reveal to someone else is no longer private, but the defenses don't hold up.
"I think basically what's happened is the government operates by secrecy and people don't know these devices are being used, in particular in criminal cases. If it's not known, and a warrant isn't requested, and after let's say someone's been convicted, it's all too easy for the government to say we got it this way and this way," she told VICE News.
Schwartz pointed out that when defense attorneys and privacy advocates have pushed law enforcement to get more information on the use of StingRay technology, many agencies have invoked a non-disclosure agreement signed by the agency with the corporation that makes the devices, Harris Moore.
But police departments also sign agreements with the FBI to not disclose details about StingRay. Documents obtained in April by the Guardian showed the FBI requested that police departments to decline sharing any information about it and to notify the FBI when requests were made.
USA Today reported that Baltimore signed a nondisclosure form with the FBI, which asks that all agencies do the same in order to use the technology. The Baltimore Police Department declined to comment on the USA Today investigation.