Appeals Court Says Warrantless Use Of Stingray Devices Probably OK


An interesting ruling [PDF] has been handed down by the Seventh Circuit Court of Appeals on the warrantless use of Stingray devices to locate individuals. Wisconsin police used an IMSI catcher to track down Damian Patrick for a parole violation. He was arrested while sitting in a car on a public street.

Multiple factors played into the court’s decision, which found that using Stingrays without a warrant to locate people was not a Fourth Amendment violation. But it’s not quite as simple as it might first appear to be. Complicating things were the circumstances of the arrest and arguments raised in Patrick’s suppression request.

Patrick argued that the location tracking warrant (not a search warrant) was invalid. First, the tracking warrant made no mention of the Stingray the police used to locate him. Second, he argued that his personal location was not “contraband or the proceeds of a crime,” making his location “off limits” to the Wisconsin PD’s investigatory efforts. The court disagrees.

That sounds like an attempt to resurrect the “mere evidence” doctrine that the Supreme Court disapproved in Warden v. Hayden, 387 U.S. 294 (1967). Hayden authorized the use of warrants to get evidence to locate a wanted person. See also Steagald v. United States, 451 U.S. 204 (1981) (search warrant to enter house to look for person to arrest).

Police were entitled to use a warrant to obtain data that would help them track down Patrick’s location. Indeed, they were entitled to arrest him without a warrant of any kind, let alone the two warrants they had. United States v. Watson, 423 U.S. 411 (1976), holds that probable cause alone is enough for an arrest in a public place.

That statement, though, only refers to the arrest warrant. There’s the matter of the location tracking warrant — which only specified the use of “cell phone data,” not a cell tower spoofer. That isn’t addressed until later in the decision, but in terms of locating Patrick, the court feels his public location (parked on a city street) diminishes any expectation of privacy in his location. Once eliminated by the court’s reasoning, it no longer matters what method the police used to locate him, at least according to the majority.

Probable cause to arrest Patrick predated the effort to locate him. From his perspective, it is all the same whether a paid informant, a jilted lover, police with binoculars, a bartender, a member of a rival gang, a spy trailing his car after it left his driveway, the phone company’s cell towers, or a device pretending to be a cell tower, provided location information. A fugitive cannot be picky about how he is run to ground. So it would be inappropriate to use the exclusionary rule, even if the police should have told the judge that they planned to use a cell-site simulator to execute the location warrant.

The appeals court never addresses whether or not the use of a Stingray constitutes a search. It weighs it against precedent in terms of call records and GPS tracking devices, and concludes that neither of those constitute a search either. (Although it does grant that the Supreme Court’s Jones decision raises questions partially related to Stingray deployment — like how long the device was in use and how precise the location data collected was.)

The government, however, conceded that it was a search (“for the purposes of this litigation“), but argued the lack of information about the device on the affidavit did not make the tracking warrant invalid. The court agrees and finds no reason to suppress the evidence. As it sees it, where Patrick was found is more important than how he was found. In the eyes of the majority, there was no privacy violation and Patrick doesn’t have standing to challenge the government’s search on these grounds.

We can imagine an argument that it will often be unreasonable to use a cell‐site simulator when phone company data could provide what’s needed, because simulators potentially reveal information about many persons other than the suspects. (The contrary argument is that data from simulators is current, while data relayed through phone companies’ bureaucracies may arrive after the suspect has gone elsewhere.) But if the problem with simulators is that they are too comprehensive, that would not lead to suppression—though it might create a right to damages by other persons whose interests were unreasonably invaded. Patrick is not entitled to invoke the rights of anyone else; suppression is proper only if the defendant’s own rights have been violated.

The court goes on to point out that no other appeals court has handled the issue of the constitutionality of Stingray searches… and that it’s not interested in being the first to do so.

Questions about whether use of a simulator is a search, if so whether a warrant authorizing this method is essential, and whether in a particular situation a simulator is a reasonable means of executing a warrant, have yet to be addressed by any United States court of appeals. We think it best to withhold full analysis until these issues control the outcome of a concrete case.

The dissenting opinion, written by Chief Judge Diane Wood, runs far longer than the majority’s opinion. Wood raises several questions about the assumptions made by the court. First, Wood points out the government has been willing to engage in very dubious practices just to keep the existence and use of Stingray devices secret.

This is the first court of appeals case to discuss the use of a cell‐site simulator, trade name “Stingray.” We know very little about the device, thanks mostly to the government’s refusal to divulge any information about it. Until recently, the government has gone so far as to dismiss cases and withdraw evidence rather than reveal that the technology was used.

Because of this, no one other than the law enforcement agents who deployed the device know exactly how it was operated and what it collected. The DOJ guidance quoted in the majority opinion does not provide any details on device usage or capabilities — only that it has recommended the use of search warrants going forward by DOJ components. There is nothing in it that declares this guidance should be followed by local law enforcement agencies.

Wood points out that software packages for Stingray devices expand their capabilities significantly, allowing them to intercept communications as well as location data. Because the government on all levels refuses to discuss Stingray deployments, the court is left to assume all it did was scoop up location data. But that assumption may be incorrect, and if so, the government has zero interest in correcting the record.

In this case, the location warrant authorized only methods of fixing Patrick’s location that involved gathering information that would reveal his phone’s connection with cell‐ phone towers. The Supreme Court has recognized that a search of cellphone data requires a warrant. See Riley v. California, 134 S. Ct. 2473, 2494–95 (2014) The authorization of the collection of location data cannot be expanded to permit a search of the con‐ tents of Patrick’s cell phone. If the Stingray gathered information from the phone that went beyond his location, such a “search” of his phone would have been unauthorized, and suppression of the additional information (which might have pinpointed Patrick’s location) would likely be required.

Not only would the Supreme Court’s Riley decision be implicated by this interception, but Title III (which controls wiretap use) would be as well. But, once again, the court is forced to assume the only thing collected was location data because that’s all the government is willing to confirm. The government asserts that the Stingray collected nothing more than the same records it could have obtained without a warrant directly from service providers, albeit not in real time. However, there is seemingly no way to verify this as the government has refused to provide more details.

We are in all likelihood not looking at two interchangeable tools for gathering exactly the same information. If the facts ultimately show that the MPD had gathered the identical information in the same manner that Sprint would have used, I would concede that there is no problem. In such a case, the only difference between using the Stingray and obtaining the information from Sprint would be who gathered the information.


We do not know whether the warrant’s authorization of Sprint to “initiate a signal to determine the location of the subject’s mobile device on the service provider’s network or with such other reference points as may be reasonable available” also describes the working of the Stingray that was used. If so, perhaps all is well. If the Stingray works in a different manner—for instance, by forcing the cell phone to transmit location data housed inside the cell phone rather than using a signal to locate the cell phone on the Sprint network—it might not.

The dissenting opinion also finds the majority’s reasoning that the probable cause to arrest — along with the defendant’s public location — excuses the lack of information in the warrant specifying the use of a Stingray device.

I recognize that Strieff contains language that could be stretched to suggest that a warrant’s existence, regardless of the actual causal chain, is sufficient attenuation. But elsewhere in the opinion the Court emphasized not only that the “warrant was valid” and “predated [the officer’s] investigation,” but also that it “was entirely unconnected with the stop,” and that the officer’s decision to arrest the defendant was “a ministerial act that was independently compelled by the pre‐existing warrant.”

Here, the use of the Stingray led to the arrest, and neither the arrest nor the search was a ministerial act.   It oversimplifies Strieff to focus solely on whether an intervening circumstance can be identified. That is important, but it is not enough by itself. Strieff, like all attenuation cases, also rests on two other factors: (1) the “temporal proximity” between the potentially unlawful action and the “search,” and (2) the culpability of the police misconduct. Id. As in Strieff, the relative temporal proximity in our case between the potentially illegal conduct and the search weighs against attenuation. But unlike the situation in Strieff, the facts here do not permit us to say that the MPD’s conduct was merely negligent: the police knew what they were doing. Purposeful evasion of judicial oversight of potentially illegal searches is exactly the kind of “police misconduct … most in need of deterrence.”

This decision is mostly a punt by the appeals court. It routes around most of the Fourth Amendment implications by relying heavily on the arrest warrant rather than the location warrant. The majority raises few challenges to the government’s assertions about its Stingray use and obviously feels the issues it avoided dealing with here would be better dealt with anywhere but in its courtroom. While it is true there were any number of ways the police could have located Patrick, the fact is it used a Stingray device — one it didn’t disclose in its warrant request — to do so. The decision to give the government a pass only encourages the culture of secrecy surrounding the use of cell tower spoofers.

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