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Fourth Circuit: Long-Term Aerial Surveillance That Reveals ‘Whole of Individuals’ Movements’ Constitutes Search Without a Warrant, Violates Fourth Amendment

by Douglas Ankney

On rehearing en banc, the U.S. Court of Appeals for the Fourth Circuit concluded that the Aerial Investigation Research (“AIR”) program—a first of its kind aerial surveillance initiative—enabled police to deduce the whole of individuals’ movements. Therefore, accessing its data is a search, and its warrantless operation violates the Fourth Amendment.

In December 2019, Baltimore Police Department (“BPD”) Commissioner Michael Harrison announced the AIR program, which was a renewed aerial surveillance partnership with Ohio-based Persistent Surveillance Systems (“PSS”). [Note: PSS has since rebranded as “Community Support Program,” but the Court continued to refer to it as PSS.] The AIR program, using multiple airplanes flying in distinct orbits above Baltimore equipped with PSS’ camera technology known as the “Hawkeye Wide Area Imaging System,” captured roughly 32 square miles per image per second. The planes flew at least 40 hours each week, obtaining an estimated 12 hours of coverage of around 90% of the city each day.

A Professional Services Agreement (“PSA”) limited collection to daylight hours and limited the photographic resolution to one pixel per person or vehicle, though neither restriction is required by the technology. Any single AIR image—captured once per second—included around 32 square miles of Baltimore and could be magnified to a resolution where people and cars are individually visible as blurred dots or blobs.

The planes transmitted the photographs to PSS “ground stations” where contractors used the data to “track individuals and vehicles from a crime scene and extract information to assist BPD in the investigation of Target Crimes.” Target Crimes included homicides, attempted murder, shootings with injury, armed robbery, and carjacking.

The contractors prepared reports and briefings within 18 hours, as requested by BPD officers investigating a particular Target Crime. These reports could include information from both before and after the crime such as “observations of driving patterns and driving behaviors;”the “tracks” of vehicles and people at the scene; the locations of those vehicles and people visited; and the tracks of the people whom those people met with and the locations they came from and went to.

PSS integrated “BPD systems” into its software “to help make all of the systems work together to enhance their ability to help solve and deter crimes.” The PSA listed BPD’s dispatch system, BPD’s “Citi Watch” security cameras, BPD’s “Shot Spotter” gunshot detection, and BPD’s license plate readers as systems to be integrated.

AIR data were to be stored on PSS’ servers and retained for 45 days, but nothing in the PSA specified an obligation or process for data deletion. Further, PSS maintained the reports and related images “indefinitely as necessary for legal proceedings and until relevant statutes of limitations expire.”

Plaintiffs, Leaders of a Beautiful Struggle, include lead Plaintiffs Ericka Bridgeford and Kevin James. Bridgeford leads Ceasefire Baltimore—a grassroots group of community advocates seeking to end or reduce gun violence. Necessarily, Bridgeford visits scenes of gun violence as soon as possible after a crime takes place. Plaintiffs filed suit on April 9, 2020, against BPD and Harrison challenging the constitutionality of the AIR program under the Fourth Amendment.

Plaintiffs requested, inter alia, that Defendants be enjoined from operating the AIR program and “collecting or accessing any images through the program.” Plaintiffs sought a preliminary injunction. The U.S. District Court for the District of Maryland denied the requested preliminary injunction, and Plaintiffs appealed.

While the appeal was pending, the AIR program ended. Ultimately, the Defendants deleted all data except that pertaining to 200 cases still active, which was about 14.2% of all captured images or 264.82 hours of coverage comprising 953,337 images. Additionally, “the 200 investigation briefings [reports] and other ground-based videos” were uploaded to BPD’s The issue remaining on appeal was the Defendants’ continued access to this information without a warrant.

The Fourth Circuit observed, “[a] preliminary injunction is an extraordinary remedy.” In re Search Warrant Issued June 13, 2019, 942 F.3d 159 (4th Cir. 2019). To justify its application, a plaintiff must establish that (1) they are likely to succeed on the merits; (2) they are likely to suffer irreparable harm absent preliminary relief; (3) the balance of equities favors relief; and (4) the relief is in the public interest. Id. The “basic purpose of the Fourth Amendment” is “to safeguard the privacy and security of individuals against arbitrary invasions by government officials.” Carpenter v. United States,138 S. Ct. 2206 (2018).

Since the time of the Founding generation, “technology has enhanced the Government’s capacity to encroach upon areas normally guarded from inquisitive eyes.” Carpenter. The U.S. Supreme Court in Carpenter applied the Founders’ principles to “a new phenomenon: the ability to chronicle a person’s past movements through the record of [their] cell phone signals [i.e., cell-site location information (“CSLI”)].” The Carpenter Court ruled that this ability invades a person’s reasonable expectations of privacy, and thus, accessing CSLI constitutes a search for Fourth Amendment purposes.

The touchstone in Carpenter was the line of cases addressing “a person’s expectation of privacy in [their] physical location and movements.” On the one hand, the U.S. Supreme Court had held that placing a tracking beeper on a suspect’s vehicle that enabled police to follow him was not a search because people have no expectation of privacy in their public “movements from one place to another.” United States v. Knotts, 460 U.S. 276 (1983). The Court in the current case explained that the beeper at issue in Knotts “only augmented, to a permissible degree, warrantless capabilities the police had even before the technology.” See Kyllo v. United States, 533 U.S. 27 (2001). But on the other hand, the U.S. Supreme Court stated that police using a GPS-tracking device to remotely monitor and record a vehicle’s movements over 28 days “impinges on expectations of privacy.” United States v. Jones, 565 U.S. 400 (2012). The Court in the current case explained that although Jones was decided on trespass principles, five Justices agreed that society’s expectation is that the police will not “secretly monitor and catalogue every single movement of an individual’s car for a very long period.” Jones (see Alito, J., concurring, and Sotomayor, J., concurring).

In Carpenter, the Supreme Court determined the CSLI “provides an all-encompassing record of a holder’s whereabouts,” and such a “deep repository of historical location information” opens “an intimate window into a person’s life.... [R]evealing not only [their] particular movements, but through them [their] familial, political, professional, religious, and sexual associations.” Therefore, Carpenter solidified the line between short-term tracking of public movements via an electronic device like a beeper and prolonged tracking and recording that can reveal intimate details through habits and patterns. The latter form of surveillance invades the reasonable expectation of privacy that individuals have in the whole of their movements and therefore require a warrant. Id.

In the instant case, the Fourth Circuit observed the AIR program was more like the CSLI in Carpenter than the beeper in Knotts. The AIR program tracked every movement of every person outside in Baltimore. The data were a “detailed, encyclopedic” record of where everyone came and went within the city during daylight hours and was retained for 45 days—enabling law enforcement to travel back in time to observe a target’s movements forwards and backwards. In conjunction with BPD’s other surveillance systems—such as CitiWatch cameras and license plate readers—those “blurred dots and blobs” turned into recognizable people and vehicles. The BPD could access the data to track an individual’s movements and through them, their familial, political, professional, religious, and sexual associations. The Court concluded the AIR program enabled police to deduce from the data the whole of individuals’ movements, was not short-term, and went beyond mere augmentation of ordinary law enforcement capabilities. Thus, the Court held that accessing the data constitutes a search and its warrantless operation violates the Fourth Amendment. As such, the Court further held that the Plaintiffs’ Fourth Amendment challenge was likely to succeed on the merits.

Having satisfied the first factor favoring a preliminary injunction, the Court determined the Plaintiffs satisfied the remaining three. A likely constitutional violation satisfied the irreparable harm factor. See Mills v. District of Columbia, 571 F.3d 1304 (D.C. Cir. 2009). The balance of equity favored preliminary injunction because the State is in no way harmed when prevented from acting in an unconstitutional manner. Giovani Carandola, Ltd. v. Bason, 303 F.3d 507 (4th Cir. 2002). Finally, public interest favors protecting constitutional rights. Id. Thus, the Court held that the district court erred in denying Plaintiffs’ motion.

Accordingly, the Court reversed and remanded for further proceedings consistent with its opinion. See: Leaders of a Beautiful Struggle v. Baltimore Police Department, 2 F.4th 330 (4th Cir. 2021). 

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Leaders of a Beautiful Struggle v. Baltimore Police Department



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