Appeals Court Rules Aerial Police Tracking of Citizens Violates Fourth Amendment

Baltimore kept tabs on citizens' movement across 90 percent of the city, without a warrant, to investigate crimes.


The use of surveillance planes in Baltimore to track people's movement for long periods without a warrant is a violation of the Fourth Amendment, a federal appeals court ruled Thursday.

The case revolved around an air surveillance program run by the Baltimore Police Department (BPD) called Aerial Investigation Research (AIR). Beginning in 2016, BPD announced it would be using cameras attached to planes to conduct aerial surveillance to fight crime. The program was discontinued in response to public anger over the snooping.

But in 2019, the program returned as AIR. The city approved a contract between BPD and a private company in April 2020. During daylight hours, the planes would fly over the city recording images of the outdoor activity of about 90 percent of Baltimore. The images were stored and could be used to track the movements of individuals connected to particular crimes like homicides, carjackings, and armed robberies.

But the police did not request a warrant to go back and look at this collected data. A community activist group, Leaders of a Beautiful Struggle, represented by the American Civil Liberties Union (ACLU), sued, noting that its advocacy involves traveling to and visiting locations of crimes and gun violence, meaning that its members' movements could be tracked by AIR. It argued that this unwarranted surveillance constituted a violation of members' Fourth Amendment rights and asked the courts to issue an injunction to stop it.

Concerns about the use of aerial surveillance grew throughout 2020 into 2021 as Americans discovered the Department of Homeland Security used drones to spy on protesters who took to the streets to demand policing reform after George Floyd's death. Among those who signed on to amici briefs supporting Leaders of a Beautiful Struggle were the NAACP, the Electronic Frontier Foundation, the Brennan Center for Justice, and the limited-government conservatives of the FreedomWorks Foundation.

On Thursday, judges from the U.S. 4th Circuit Court of Appeals overruled a lower court decision and agreed with the ACLU. The majority opinion, written by Chief Judge Roger L. Gregory, determined that "because the AIR program enables police to deduce from the whole of individuals' movements, we hold that accessing its data is a search, and its warrantless operation violates the Fourth Amendment."

The majority opinion draws heavily from the Supreme Court's 2018 Carpenter v. United States decision, which held that warrantless tracking of people via their cellphone location data violated the Fourth Amendment. In that opinion, Chief Justice John Roberts wrote, "A person does not surrender all Fourth Amendment protection by venturing into the public sphere." That explanation is used here by the 4th Circuit to explain why BPD can't use aerial surveillance data for the same purpose.

"Carpenter solidified the line between short-term tracking of public movements—akin to what law enforcement could do '[p]rior to the digital age'—and prolonged tracking that can reveal intimate details through habits and patterns," Gregory wrote. "The latter form of surveillance invades the reasonable expectation of privacy that individuals have in the whole of their movements and therefore requires a warrant."

Gregory goes on to compare the AIR program to "attach[ing] an ankle monitor" to every person in Baltimore. If police determine that someone is connected to a crime, that person's past six weeks of movements would be stored via AIR.

Baltimore suspended the program in February of this year, which the police then tried to use to get the case declared moot to avoid a ruling. But the court majority determined that the debate over the use of aerial surveillance constitutes a "live controversy" and ruled anyway. The lower court's decision has been reversed and the case remanded back for reconsideration.