Key Points

  • The Fourth Circuit held that real-time use of a cell-site simulator to locate a cellphone inside a private residence constitutes a Fourth Amendment search, the first federal appeals court to squarely decide the question.
  • Despite finding a constitutional violation, the court granted qualified immunity to the detectives because no precedent clearly established the law at the time of Andrews's 2014 arrest.
  • The opinion documents an FBI nondisclosure agreement that required Baltimore police to notify the FBI before disclosing Hailstorm use and contemplated prosecutors seeking dismissal rather than revealing the technology.
  • Andrews spent nearly two years in pretrial detention before Maryland courts suppressed the evidence; he will recover no damages for that detention.
  • Judge Quattlebaum concurred in the judgment but questioned whether the majority should have reached the constitutional merits when deciding the case on qualified immunity grounds.

The Fourth Circuit ruled Thursday that police use of a cell-site simulator to track a suspect's cellphone inside a private residence violates the Fourth Amendment, becoming the first federal appeals court to squarely hold that the surveillance technology constitutes a search deserving constitutional protection.

But Kerron Andrews, the young man whose nearly two years of pretrial detention hinged on that unlawful search, will recover nothing. The same opinion granted qualified immunity to the detectives who tracked him, finding that no precedent had clearly established the constitutional violation at the time of his 2014 arrest.

Judge Berner wrote for the court in the September 24 decision, joined by Judge Heytens. Judge Quattlebaum concurred in the judgment but questioned whether the majority should have reached the constitutional question at all when the case could be resolved on immunity grounds alone.

The decision arrives more than a decade after Baltimore police used a device called Hailstorm to pinpoint Andrews inside a townhome on Clifton Avenue while investigating a triple shooting. An FBI nondisclosure agreement kept the technology secret from Andrews's defense counsel for a full year after his prosecution began—an agreement that explicitly contemplated prosecutors seeking dismissal rather than revealing the surveillance tool in court.

Cell-site simulators, sometimes called Stingrays, function by impersonating a cell tower. "In response to signals emitted by the simulator, every cell phone and other cellular-enabled device in the area [using the same service provider] identifies the simulator as the best local cell tower and transmits a connection signal containing that device's unique identifier to the simulator," the court explained. Officers can home in on a suspect's cellphone by walking through an area observing signal strength and direction.

Andrews became a suspect in 2014 after a shooting that injured three people. Police obtained an arrest warrant but could not determine where he lived. Using carrier data, they narrowed his location to approximately thirty-five townhomes. Detective John Haley then deployed the Hailstorm, walking the blocks until the device pinpointed Andrews inside a specific unit. After obtaining consent to enter, officers found Andrews on a couch with his cellphone. During a subsequent search, they discovered a gun in the cushions.

Andrews's counsel repeatedly asked how police had located him, but prosecutors did not disclose the Hailstorm until a year into the proceedings. A Maryland trial court suppressed the evidence, and an intermediate appellate court affirmed, holding that use of the simulator constituted a search. With the evidence gone, prosecutors dropped the case. Andrews was released after nearly two years in pretrial detention awaiting trial on charges that were never adjudicated.

Andrews then sued the detectives under Section 1983, seeking damages for his detention. The case proceeded through a tortuous procedural history spanning a decade, including multiple remands for discovery about the Hailstorm technology and the department's policies, before reaching the Fourth Circuit for final resolution.

Judge Berner traced the constitutional analysis through the Supreme Court's recent decisions on cellphone location surveillance. Neither Carpenter v. United States, decided in 2018, nor Chatrie v. United States, decided this year, directly addressed cell-site simulators. But both established that individuals maintain a reasonable expectation of privacy in their cellphone's location, even when that data passes through third parties.

The location where police deployed the technology heightened the constitutional stakes. "[P]rivate residences are places in which the individual normally expects privacy free of governmental intrusion not authorized by a warrant, and that expectation is plainly one that society is prepared to recognize as justifiable," Judge Berner wrote, quoting the Supreme Court's 1984 decision in United States v. Karo.

The simulator effectively "crack[ed] open the front door" of the townhome to reveal Andrews inside, Judge Berner wrote, invoking language from Kyllo v. United States, the 2001 decision on thermal imaging. "We therefore conclude," Judge Berner wrote, "that the use of a cell-site simulator constitutes a search, deserving of the protection of the Fourth Amendment."

That conclusion did not deliver Andrews a remedy. Qualified immunity shields government officials from civil damages unless they violated a right "sufficiently clear that every reasonable official would have understood that what he is doing violates that right." No federal circuit had addressed whether cell-site simulators require a warrant before Thursday's decision. Carpenter came four years after Andrews's arrest; Chatrie came this year. Given the absence of clearly established law, the detectives were entitled to immunity.

Andrews also sued the Baltimore City Police Department, arguing it maintained unconstitutional policies of using simulators without warrants and withholding information about the technology. The FBI nondisclosure agreement required the department to notify the FBI before any disclosure and stated that "the Office of the State's Attorney for Baltimore [to], at the request of the FBI, seek dismissal of the case in lieu of using or providing, or allowing others to provide, any information concerning the Harris Corporation wireless collection equipment/technology."

The court affirmed summary judgment for the municipal defendants but echoed concerns the district court had expressed. "[L]aw enforcement may not rely on a private nondisclosure agreement as an excuse to conceal or obfuscate important information when seeking a search warrant or information it is required to disclose in court proceedings," Judge Berner wrote.

The practical effect is to establish that law enforcement in the Fourth Circuit must now obtain a warrant before using a cell-site simulator to track a suspect inside a residence. The constitutional holding may influence courts in other circuits or future petitions for certiorari.

For Andrews, the timing of constitutional law worked against him. He spent nearly two years in detention for a crime he was never convicted of, saw the evidence suppressed because of an unconstitutional search, and cannot recover damages because the violation was not clearly established until the very opinion that recognizes it. Michael A. Pichini of Goodell, DeVries, Leech & Dann argued for Andrews. Natalie Rose Amato of the Baltimore City Law Department argued for the defendants. The case is Andrews v. Baltimore City Police Department, No. 18-1953.