Mimesis Law
1 July 2020

Maryland Appeals Court Requires Warrant For Stingray

Apr. 4, 2016 (Mimesis Law) — In a victory for the 4th Amendment, the Maryland Court of Special Appeals upheld a ruling requiring a search warrant before police can use a stingray. Used by the FBI and police across the county, stingrays, also called cell site simulators and IMSI catchers, spoof cell towers to collect cell phone information without detection.  And they collect calls and text from everyone in their reach, innocent callers as well as law enforcement targets.

Over the last couple of years, the use of these secret devices became public, despite nondisclosure agreements that required prosecutors to dismiss cases rather than give up information about their use. Cops went so far as to lie to judges as to the source of information to conceal their existence.

With publicity and concern rising last year, many states began passing or considering laws requiring police to obtain a warrant before utilizing these devices. Late last year, the Department of Justice issued new guidelines calling for a warrant in most instances. Court cases involving these devices also started winding their way through the legal system. The Maryland case is the first appellate decision in the nation to address the 4th Amendment implications of these devices.

Law enforcement in Maryland treated the Stingray device much like a pen register. Because of the limited data collected by a pen register (dialed numbers), courts routinely grant their use based on reasonable suspicion, a lower standard of proof than probable cause.

In this case, the officer obtained an order and began using a pen register. Baltimore City police officials contacted Sprint and obtained not only past cell tower information, but pen register data as well as GPS precise locations in a real-time format. As police began to receive tracking information under the pen register, they proceeded to the general vicinity of the phone, within 200 to 1600 meters. It was at this point that police deployed a stingray (under the brand name “Hailstorm,” a newer version of the stingray) to narrow their search within an apartment complex identified by the pen register. However, law enforcement did not obtain any type of court order or warrant to utilize the Stingray/Hailstorm device.

After testimony describing the use of the Hailstorm device, it became clear the device, while similar to a cell tower, differed in one very significant manner: the cell tower is used when calls are made or the phone is otherwise in use, yet the Hailstorm seeks out an otherwise inactive phone and requests it data. With a cell tower, the phone and the user ultimately are generating the request or contact with the tower. With Hailstorm, the device is reaching out to the phone and forcing it to provide data and GPS location within feet or yards.

Recognizing the stingray as much more intrusive than a pen register, the court equated the device to a real-time tracking device which requires probable cause:

We conclude that people have a reasonable expectation that their cell phones will not be used as real-time tracking devices by law enforcement, and—recognizing that the Fourth Amendment protects people and not simply areas—that people have an objectively reasonable expectation of privacy in real-time cell phone location information.

Thus, we hold that the use of a cell site simulator requires a valid search warrant, or an order satisfying the constitutional requisites of a warrant, unless an established exception to the warrant requirement applies.

Though this case answers the 4th Amendment question regarding use of the Hailstorm/Stingray device, it does not answer the similar question of real-time tracking posed by the expansion of the pen register, as that issue was not raised. The pen register authorized in this case also allowed for Sprint to provide historical and ongoing GPS location data. As such, the pen register became much more than a recording of numbers dialed; it too became a law enforcement tracking device. It seems this expansion would also cause the same 4th Amendment concerns.

Did the government use the guise of a pen register to bypass warrant requirements and keep their Hailstorm technology secret? As the court noted, the original application for the pen register appears to be an effort to conceal the technology and use of the Hailstorm. The application for the pen register indicated the individual’s location “will be obtained by learning the numbers, locations and subscribers of the telephone number(s) being dialed or pulsed from or to the aforesaid telephone.” Yet, it went further to request and allow tracking GPS coordinates and apparently utilizing the secret government technology to reach within the walls of the home and locate the individual sought:

ORDERED, . . . [t]he Agencies are authorized to employ surreptitious or duplication of facilities, technical devices or equipment to accomplish the installation and use of a Pen Register \ Trap & Trace and Cellular Tracking Device, unobtrusively and with a minimum of interference to the service of subscriber(s) of the aforesaid telephone, and shall initiate a signal to determine the location of the subject’s mobile device . . .  (Emphasis added.)

All in the name of the pen register statute that requires less than probable cause. And, in the name of a statute that doesn’t authorize cellular tracking per se. Did the magistrate issuing the order realize the government’s application expanded beyond the limits of the statute? Did the government tell the magistrate? In this case, it appears we may never know, as this issue wasn’t raised. But going forward, it certainly lays out a case for better checks and balances on the common practices of pen registers and technology. Perhaps with technological advances, it’s time that pen registers be more highly scrutinized and require probable cause. Otherwise, they should be limited to their origin: identifying numbers dialed.

3 Comments on this post.

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  • Mike
    4 April 2016 at 1:32 pm - Reply

    Before cell phones, was a warrant needed for a telephone company to provide the location (address) of a landline telephone?

    • sirnephilim
      5 April 2016 at 1:54 am - Reply

      Speaking as a lay person but also an ex phone phreak in the 80’s and 90’s, officially the answer was yes. However, it wouldn’t have been uncommon for law enforcement to obtain this information independently and engage in a little parallel reconstruction.

      The issue was muddied by the availability of reverse lookup phone directories (listed by phone number and giving name and address) in most areas, which were nominally restricted due mostly to obscurity but certainly available to law enforcement agencies. Most people with a landline were listed in those, obviating the need for any warrant. (Incidentally, http://www.whitepages.com/reverse_phone – you’re probably on it.)

      As a teen I was questioned several times about things the police could not have connected to me without violating an amendment or two. Also phreaks in that era would attract the attention of the Secret Service, because apparently messing with the phone system was every bit as heinous as counterfeiting money or threatening the President. Go figure.

  • In Maryland, Business As Usual For The Fourth Amendment
    28 April 2016 at 9:41 am - Reply

    […] 28, 2016 (Mimesis Law) — Earlier this month, my colleague and fellow Fault Lines contributor, JoAnne Musick, discussed a Maryland Court’s holding that police must get a warrant before using a Stingray to […]