The Query Was a Search

One evening in May a Tulsa County deputy sheriff, parked on the side of an Oklahoma highway, watched a Mazda SUV with California plates go by, pulled out to follow it, and ran the plate through Flock, a commercial network of automated licence-plate cameras whose records are shared with police across the country. Asked by the systems he searched for a reason, he entered “traffic violation” and “investigation.” On Thursday, 1 October, Judge Sara E. Hill of the federal district court for the Northern District of Oklahoma held that the query was a search under the Fourth Amendment, that it needed a warrant, and that everything the deputy found after he ran it must be kept out of the prosecution’s case.

The case is a criminal one, United States v. Kyle, No. 26-cr-00189, and the ruling came on the defendant’s motion to suppress. According to the opinion, Deputy Freddie Alaniz, a drug-interdiction officer who has served on a Drug Enforcement Administration task force, followed the car “for no apparent reason other than the fact that it had a California license plate.” His searches of Flock and a second system, VehicleManager, showed the car travelling from Locust Grove, Oklahoma, toward the California and Arizona border and heading back toward Missouri after a short stay. He stopped the driver for following too closely, questioned her about the trip while still reviewing the camera data, and gave her a written warning. Then he asked to search the car. She refused; he told her she was being detained so that his dog could sniff it. The dog alerted and the search led to her arrest. 404 Media and TechCrunch reported that 91 pounds of methamphetamine were found; the opinion does not say what the search turned up.

The opinion suppresses the evidence twice over, and the first ground has nothing to do with cameras. Judge Hill found the stop itself lawful: the driver had left about 30 feet between her car and the one ahead. But the stop ended when the deputy handed back her licence, and keeping her there for a dog sniff required reasonable suspicion of some other crime. The government offered, among other things, a short trip to California, a lot of luggage, a rental car, a cigarette and nervousness. Taken together, the court found, they did not amount to reasonable suspicion. “Many of us drive longer than we want to get to a desired destination,” the judge wrote, “or to no destination at all other than the road and sights ahead.” On that ground alone, all evidence from the extended stop was suppressed.

The second ground is the one that has drawn attention, and the opinion admits it is unusual. “Neither the Tenth Circuit nor the Supreme Court have decided whether law enforcement’s use of ALPR technology is a search for Fourth Amendment purposes,” it says, and “nearly every court examining the issue to date has determined that ALPR technology use is not a search under the Fourth Amendment because people have no reasonable expectation of privacy in their movements on public streets.” The opinion cites three such rulings by federal courts in Oklahoma, one of them from Judge Hill’s own district in August 2025.

From the beeper to the geofence

The decisions on the other side rest on United States v. Knotts, a 1983 case in which police put a beeper in a container of chemicals and used it to follow a car. The Supreme Court held that “[a] person travelling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another.” It also answered the defendant’s warning about round-the-clock surveillance: if “dragnet type law enforcement practices” should eventually occur, “there will be time enough then to determine whether different constitutional principles may be applicable.” Judge Hill took the Court at its word. More than 40 years later, she wrote, “this Court is now faced with technology that appears to be approaching the dragnet type law enforcement practice Mr. Knotts warned of.”

Two later cases supplied the principle she applied. In Carpenter v. United States (2018) the Court held that obtaining a person’s historical cell-site records was a search, saying that a majority of the Court had already recognised that “individuals have a reasonable expectation of privacy in the whole of their physical movements.” Then on 29 June this year, in Chatrie v. United States, a five-justice majority written by Justice Elena Kagan held that police conducted a search when they obtained a bank robbery defendant’s Location History from Google under a geofence warrant. Knotts, the majority said, “was explicit in keeping its holding cabined to that rudimentary technology.”

Judge Hill accepted that licence-plate data “is not the same fine-tuned level of detail that something like a cell phone reveals.” The deputy had at least 30 days of sightings in many states, though nothing from California, and more than fifty records of this one car. What mattered to her was how the records came to exist. “This is a type of indiscriminate mass surveillance,” she wrote. “It is not targeted on a single individual, as in Carpenter. It is a tool that collects information about all vehicles that pass by any network-connected camera at all times, and it serves up the information to law enforcement on demand.” She noted that the camera on the deputy’s own patrol car feeds the network. A friend might say, “Hey, I saw you out driving by the store last week,” the opinion observes; no one expects a stranger to produce a 30-day log of everywhere the car has been. “It is not too much to draw the line at indiscriminate mass surveillance.”

A ruling that binds one case

A district judge’s opinion binds no other court, and the courts are not lined up behind this one. In September, as Orin Kerr of Stanford Law School noted, the federal district court for the Central District of California held in United States v. Riley that police queries of two cities’ Flock cameras, which in Kerr’s summary yielded four photographs each, were not a search, because the data “could not create ‘an all-encompassing record’” of his whereabouts. In January, before Chatrie, Judge Mark S. Davis in Norfolk, Virginia, granted the city summary judgment in Schmidt v. City of Norfolk, a civil challenge by two plaintiffs to the city’s Flock cameras, finding they had not shown that the cameras captured enough data to reveal the whole of their movements. That case is now on appeal in the Fourth Circuit, No. 26-1227, where the city has filed a notice about its availability for the court’s argument session of 8 to 11 December. Kerr reported that the Eleventh Circuit heard argument on the question on 29 July; it had not ruled when he wrote.

The remedy in Kyle also turned on what the government did not argue. The exclusionary rule has exceptions, the best known for officers acting in good faith. In Chatrie the trial court found that the geofence warrant “plainly violates the rights enshrined in [the Fourth] Amendment” but refused to suppress under that exception. Judge Hill’s opinion says, of both grounds, that the government did not identify any applicable exception to the exclusionary rule. Federal law lets the United States appeal an order suppressing evidence before trial if the United States attorney certifies that the appeal “is not taken for purpose of delay” and that the evidence is substantial proof of a material fact; the appeal must be taken “within thirty days.” Any appeal would go to the Tenth Circuit, which, because the suppression rests on two separate grounds, could affirm on the extended stop without saying anything about cameras. On Friday the court struck the jury trial that had been set for 6 October and scheduled a status conference for Monday morning.

What the opinion leaves is a test rather than a rule. It does not say how many sightings, over how many days, turn a database query into a search; Riley found four photographs too few, and Kyle found more than fifty enough. The Chatrie majority saw the difficulty when it rejected the government’s argument that two hours of location history was too little to count: “At what point, exactly, would a non-search become a search?” Until an appeals court answers that for licence-plate networks, the answer depends on which judge is asked.

Sources

Judge Hill’s opinion and order of 1 October 2026 in United States v. Kyle (N.D. Okla. No. 4:26-cr-00189, ECF 62) was read in full on CourtListener, along with the docket entries of 2 October striking the trial date and setting a status conference. The Supreme Court’s opinion in Chatrie v. United States (No. 25-112, decided 29 June 2026), including the syllabus account of the lower courts’ rulings, and the opinion in Carpenter v. United States (No. 16-402) were read on the Supreme Court’s website. Knotts is quoted as Judge Hill and the Chatrie majority quote it and was not read separately. Judge Davis’s opinion of 27 January 2026 in Schmidt v. City of Norfolk (E.D. Va. No. 2:24-cv-00621) and the judgment were read on CourtListener, as were the appeal docket entries in No. 26-1227. The Riley decision and the Eleventh Circuit argument are described from Orin Kerr’s post at the Volokh Conspiracy (16 September); the Riley opinion itself was not read. The month of the stop and the quantity of drugs are as reported by 404 Media (2 October) and TechCrunch (3 October). 18 U.S.C. 3731 was read at Cornell’s Legal Information Institute. The parties’ motion papers were not read, and the government has not said whether it will appeal.