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  • Aaron Garavaglia

A Concluding Thought is Needed: The Legal Ambiguities of Cell-Site Simulators

Updated: Oct 18, 2023

A cell-site simulator is a “suitcase-sized device” that impersonates cell carrier-owned equipment to trick a target’s phone into connecting to it. The technology can be described as “invasive and over-broad in its collection of data” because its reach is not limited to a specific phone. The device connects to various phones in its vicinity and collects their unique identification numbers. It can emit a signal through the wall of a house and force a phone to emit information. The identification numbers are then cross-referenced against records provided by a service provider. The practice presumably continues until the user locates his target. Although similar in concept to another technological tool utilized by law enforcement – the automatic license plate reader – cell-site simulation technology is unique given its significant amount of use and attention while eluding a desperately needed redress by the Supreme Court.

Recognizing that the nation could no longer make do without any guidance, the Department of Justice released a memorandum on September 3rd, 2015 announcing “common principles” and “additional guidance” regarding the use of cell-site simulator technology. Absent two exceptions for exigent and exceptional circumstances, federal law enforcement agencies are now required to obtain a search warrant supported by probable cause in order to use a cell-site simulator. This categorically concluded the department’s prior practice of obtaining authorization by pursuing a pen register order pursuant to the Pen Register Statute. Pen register orders may be granted under a very low standard. Whereas a warrant requires probable cause, a pen register order only requires an attorney or police officer to certify that, “the information likely to be obtained . . . is relevant to an ongoing criminal investigation.

As beneficial to the nation’s practitioners this memorandum will be as a reference text, it is unfortunate that state and local law enforcement agencies are neither required to abide by it nor have they used it as self-guidance. Recent high-profile cases out of Baltimore and Milwaukee reminded the nation that the legality of cell-site simulator technology remains ambiguous and in desperate need of redress by the Supreme Court.

The holding in State of Maryland v. Andrews is prominent for three reasons: One, the State of Maryland acknowledged its use of cell-site simulators, forgoing its prior practice of abandoning cases whenever its methodologies were challenged; Two, the court categorically held that use of a cell-site simulator constitutes a search under the Fourth Amendment; and three, the search was not constitutionally permissible because the pen register order the Baltimore Police Department sought was not a sufficient search warrant. The case is currently on appeal.

In recent times, two federal cases have further demonstrated issues similar to what is being litigated in Andrews. These cases demonstrate the mounting pressures of a national conversation that the Supreme Court should conclude and a changing attitude among law enforcement abandoning the clandestine nature of their nondisclosure agreements by acknowledging the existence and use of cell-site simulator technologies.

Down in Richmond, a divided panel of the Fourth Circuit in United States v. Graham recently overturned the holding of a district court by finding that the government must obtain a search warrant to obtain a defendant’s “extended” location information from a cell phone provider. This case is similar to Andrews in two respects: The court rejected the government’s argument that cell-site simulator technology does not constitute a search under the Fourth Amendment, and the police chose to acknowledge their use of the technology. However, it is dissimilar to Andrews because the court found that the defendant was not entitled to an exclusionary remedy due to a good faith exception and it only addressed “extended” location information. Further, an argument that the government is arguing on appeal in Andrews was summarily rejected by the court in Graham. Whereas Maryland argued that cell-site records are information that is not protected by the Fourth Amendment because it is voluntarily shared with a third party, the cell phone provider, the court in Graham found that this argument would, “[S]imply permit the government to convert an individual’s cell phone into a tracking device by examining the massive bank of location information retained by her service provider . . . without probable cause.”

Likewise, the Seventh Circuit is now considering United States v. Patrick. The defendant was arrested for a parole violation after a Milwaukee Police Department officer noticed a handgun in the defendant’s car during a traffic stop. Similar to the police in Andrews and Patrick, Milwaukee Police were mum on the information that led them to the defendant’s location (they referenced an “unknown source” and “prior knowledge”). This changed when the defense moved to suppress, arguing that the police did not have a reasonable suspicion to seize the defendant at his particular location when the police initiated a traffic stop. A police officer then disclosed in court that the defendant's phone was being "tracked."

Andrews, Graham, and Patrick present opportunities for the Supreme Court to address the legal ambiguity of cell-site simulator technology. The crimes in controversy – murder, bank robbery, and a simple parole violation – indicate that cell-site simulators are being deployed for diverse purposes. Indeed, the Fourth Circuit in Graham questioned whether the Court will step in and categorically conclude the national conversation. Given its national prominence (Baltimore has admitted to using the device at least 4,300 times) and the waning efficacy of the government’s common arguments for a third-party information exception to the Fourth Amendment and the sufficiency of a pen register order, the Supreme Court has plenty to work with for a decision. A decision by the Court can definitively apply the “common principles” from the Department of Justice’s memorandum to state and local law enforcement agencies across the nation and ameliorate the judicial confusion that follows in the wake of the various decisions of the lower courts.


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