The DOJ is in court arguing the use of Stingray devices by the FBI and local cops shouldn't require a warrant. The government's lawyers are fighting a suppression motion by Purvis Ellis, charged with racketeering and the attempted murder of a police officer.

The events of the case happened in 2013, two years before the DOJ instructed federal agents to seek warrants when deploying Stingrays. For this investigation, the Oakland PD used a pen register order, as was the style at the time. (And perhaps still is. Despite the DOJ's internal instructions, warrant requirements are all but nonexistent when it comes to local law enforcement agencies' use of cell tower spoofers.)

As Cyrus Farivar points out, the PD's Stingray couldn't locate Ellis, so it brought in the FBI. All without warrants and all without informing the defense about the additional Stingray deployment.

Ellis was located in an East Oakland apartment several hours after a January 2013 shooting with the help of two stingrays. Prosecutors initially insisted that only one stingray was used, but, as was revealed last summer, that turned out not to be the case. The Oakland Police Department's own stingray was seemingly insufficient, so officers then called in the FBI, both times without a warrant.

The defendant is arguing the multiple warrantless Stingray deployments violated the Fourth Amendment. Considering the devices coax a location signal out of phones by aping cell towers, this differentiates Stingrays from more passive collections -- like the pen register the government didn't actually use.

The government, quite obviously, is arguing otherwise. It points out in its opposition motion [PDF] that it has all the warrant exceptions on its side:

Four gang members ambushed a young man in broad daylight, shooting him through the forehead from close range. The next day, those same men jumped, pistol-whipped and shot a police officer investigating the prior days shooting. The suspects then fled, armed with their own arsenal, as well as with the guns they had just stolen from the officer. Police surrounded the apartment complex where the men were thought to be hiding. Finding them quickly was essential. By shooting two people in a 27-hour period, the suspects including the defendant Purvis Ellis had just demonstrated an ability and willingness to kill others. So, when officers used a cell site simulator (CSS) to find Ellis, they were entirely justified by the exigent circumstances presented, rightly believing him to be armed and dangerous.

The defendants motion to suppress is meritless. The courts have not definitively decided whether use of a CSS constitutes a search triggering Fourth Amendment protections. But it largely does not matter here, since exigent circumstances amply supported a warrantless use of the device.

[...]

Other exceptions to the warrant requirement also cut against suppressing evidence. For instance, the officers acted in good faith reliance on established law the pen register statute, Supreme Court precedent, even the FBI policy at the time. Those laws and policies, combined with the dearth of binding case law on the CSS, all justified using the device without a warrant. In addition, the officers would have inevitably discovered everything they ultimately did, even had they never used the CSS. After all, they had the building surrounded by dozens of officers and SWAT team members hours before the CSS was even deployed.

It's a long list of counterarguments, most of which have some validity in this particular case. (That, of course, doesn't stop the government from using the same arguments in cases where its assertions of good faith, exigency, etc. are far more questionable. But that's how lawyering works on both sides.)

It appears the government would rather the court didn't make a determination as to whether Stingray deployments are Fourth Amendment searches. The government lets the court know what it doesn't need to do to resolve this issue in the DOJ's favor:

Whether use of a cell site simulator constitutes a search for Fourth Amendment purposes is not necessarily a question this Court needs to answer, since even if it were a search, it was amply justified under the circumstances. That said, the law supports concluding that the device in this case did not affect a search.

The following argument, however, is particularly disingenuous. The defendant argued the warrant was invalid because officers didn't let the judge know they'd be deploying a Stingray device when it got its pen register order approved. The DOJ says this shouldn't matter, as it can find very little pre-2013 evidence suggesting these devices were mentioned in previous court documents.

Since the CSS technology was still relatively new in 2013, there were simply no binding cases to direct agents and officers to disregard Smith v. Maryland and get a warrant. According to the governments research, only a few federal pre-2013 cases referenced cell site simulator, digital analyzer, triggerfish, or stingray in a relevant context. (The government found no such cases in California courts.)

Well, of course this search came up empty. For years, the FBI swore law enforcement agencies to secrecy if they acquired Stingrays, telling them to dismiss cases rather than have defendants, judges, or even some prosecutors discuss the tech in open court. The lack of DOJ search results means the NDAs the FBI forced everyone to sign worked.

By no means was CSS technology "relatively new" in 2013. Documentation of Stingray devices can be found dating back to 2006 and use of pre-Stingray "digital analyzers" dates back more than 20 years. There wasn't much courtroom discussion because the FBI actively prevented it from happening. And the DOJ knows this, as its "research" likely turned up things like this 2012 NDA on DOJ letterhead telling a New York sheriff's office to STFU about its new toy.

With no discussion, there are no binding cases. That's how the FBI wanted it. And it pays off years down the road by making it easier for the DOJ to prevail in a suppression argument without setting precedent it may find inhibiting another half-decade down the road.

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DOJ Tells Court There No Need To Establish A Warrant Requirement For Stingray Devices - Techdirt