Stingray Devices

The use of a cell site simulator, or Stingray, continues to crop up in headlines across the country.  Courts are now getting involved in addressing 4th amendment concerns, such as the device’s use without a warrant and how invasive the technology really is.  This post looks at phone tracking in general, how the Stingray operates, and various cases addressing the issue throughout the country.

A Primer on Phone Tracking

Back in the days of the mafia and organized crime, police looked for ways to monitor the phone conversations of their suspects.  Known as wire taps, law enforcement were able to monitor phone calls in real-time.  As technology developed, officers employed the use of pen registers and trap and trace devices.  In each of these instances, courts have required law enforcement to obtain a search warrant to monitor the phone calls and obtain detailed data from the phone companies.

Most modern cell phones now feature GPS technology.  GPS, and other data, is stored by the cell phone companies and law enforcement is again required to obtain warrants to access the information.  Once a warrant is approved, the law enforcement agency is able to track suspects in real-time by using GPS technology.  Every time a phone uses a carrier’s network, it pings its location off of the cell phone towers with the strongest signal.  Law enforcement can usually narrow down a phone’s location to within 20-30 meters when using the GPS technology.  But sometimes, 20-30 meters is not specific enough.  This is where the Stingray comes in to play.

What is a Stingray?

At its most basic level, a Stingray is a type of device that mimics a cell tower.  Under normal circumstances, our cell phones ping off towers that have the strongest signals.  A Stingray mimics a cell tower by putting off a much stronger and more concentrated signal in order to trick cell phones into “speaking” to the device.  The Stingray is a mobile device, usually located in a police car or truck, and when turned on, has the capability to focus on one cell phone (if the cell phone information is known) or to intercept all cell phones in the designated area.

Every phone has an Electronic Serial Number (ESN) assigned to it by the mobile carrier.  If officers have a known phone number, they can subpoena subscriber information and the phone’s ESN from the cell phone provider.  Officers will then input the ESN into the Stingray and go to a general location where they believe the phone may be located.  Once the Stingray is activated, all cell phones will attempt to “speak” to the Stingray because the phones believe the Stingray is a real cell tower with the strongest signal.   According to law enforcement testimony at a recent hearing, when a specific ESN is inputted into the Stingray, it will only track the location of that specific phone.   The Stingray is able to locate the phone within 4 meters, and is even able to tell law enforcement what floor the phone might be on.

More concerning to privacy advocates, however, is when the Stingray is used and no ESN or phone number is known.  In this instance, the Stingray collects all of the ESNs in a designated area and law enforcement must then comb through that data for commonalities.  They will then use common ESNs in locations where they believe their suspect is located to subpoena provider information for that specific ESN.

Do Officers Need a Warrant?

Until recently, Wisconsin courts were unaware that law enforcement agencies were even using this device.  Once it became known that they were utilizing the device, the courts, defense attorneys, and the state legislature began to push back.  A new state law created in 2014 now requires law enforcement to apply for a warrant when they are going to use devices acting as cell site simulators.  Despite the new law, two recent Wisconsin Supreme Court cases dealing with challenges to the use of a Stingray resulted in defeats for the defense.  So the question still remains, in Wisconsin at least, as to whether the warrant needs to specifically disclose that law enforcement will be using a Stingray, or whether it is acceptable to only state that law enforcement is permitted to use “all available technology” in its search for a suspect.

In other jurisdictions, defendants are being more successful with their challenges.  A recent Maryland case held that a warrant was required to use the Stingray, and other courts around the country are requiring law enforcement to be more specific in their warrant applications as to how the device will be used.  While not yet addressed by the United States Supreme Court, this issue will no doubt continue to be challenged and the varying court decisions are likely to make the Supreme Court interested in addressing the question once and for all.