The privacy and constitutional rights of a suspected armed robber were not infringed when cops trawled records from cellular towers near two robberies and spotted a device using his phone number.

The case concerns Charles Anthony Walker Jr, who police have charged with armed robbery at two jewelry stores in North Carolina in 2018, and who faces more than 30 years in prison. The cops investigating the case put in a request for all metadata from the nearby cell towers for an hour before the robberies and half-an-hour afterwards, and combed through those records to see if they could find any evidence that would identify the thieves.

What they found could prove to be a key piece of evidence at Walker’s trial: a cellphone number that they were able to connect to him in two different ways; by a car used in the robbery, and a phone call made to a jail months earlier.

Four days before the robbery, an employee at a store close to the jewelers noticed a car behaving strangely and suspected it was casing the joint. The worker took a photo of the grey-silver Infiniti four-door sedan, which also showed its license plate, and sent it to the cops noting his suspicions.

A grey-silver four-door sedan was also seen in security footage picking up one of the armed robbers, so investigators put two-and-two together and ran a check on the car, finding in a Carfax report that the same phone number that had appeared in the cell tower data was also connected to the Infiniti (the number had been given as a contact when it was taken in for repairs.)

Running a check on the number in federal records, it also showed up in a phone call to an inmate in Guilford County Jail in North Carolina. The phone call was recorded and investigators listened to it, hearing the caller referred to as “Preme” which the cops say is Walker’s alias. During the call, “Preme” says he is with “Malik”, which cops says refers to Malik Shawn Maynard, who is another of their robbery suspects.

Ring, ring

The cellphone number records are also important because, during the robbery, one of the three suspects was inside the jewelers, and received a call to which he responded that he was “looking at the ring right now,” something that the police argue was a coded message.

Shortly after two armed men came into the store and the other man left. Cops note that the third man did not call 911 about the armed crooks, and three men were then spotted getting into the silver car after the robbery.

The cell tower data is clearly the thread tying the case together, and so Walker’s lawyer, naturally enough, questioned the legality of the data dump in the first place. And he used what has become a landmark US Supreme Court decision from 2018, known simply as Carpenter.

In that case, the top court decided 5-4 the government violated the Fourth Amendment in the case of Timothy Carpenter who was also, coincidentally, charged with armed robbery and was tracked down by his mobile phone records.

In his case, the police went to cellular network operators and retrieved four months of location data that showed he (well, his phone) was near each of the locations under investigation when they were robbed. By gathering data on his phone over four months, the police were able to build up a pattern of his habits.

But the cops had not got a warrant to access that data, and the Supreme Court decided that they should have. That was a break from what was accepted practice at the time, based on laws written before mobile phones had become so ubiquitous.

Instead, the Supreme Court decided that cellphones contained so much personal information about the user, including their constant location, that they were deserving of greater protections and as such grabbing information on them was an unreasonable search, as defined under the Fourth Amendment.

No warrant, no case?

Getting back to the Walker case, the cops did not in fact get a warrant for the cell tower data, and the judge noted that “in this case, it is undisputed that the orders did not constitute warrants satisfying Fourth Amendment requirements.”

The judge decided nevertheless that despite it being an armed robber, and cell phone location data tied to a robbery gathered without a warrant, that the Carpenter decision did not apply.

How come?

Well, because in Carpenter’s case the cops had specifically targeted him and gone to his mobile operators and gathered months of data on his movement. By contrast, in Walker’s case, the cops had only asked for cellphone data from specific towers during specific times during which a crime was committed.

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And if that sounds like a stretch, it really isn’t given what else the Supreme Court said in its judgment. In a prescient piece of writing, the higher court noted that its decision was “a narrow one” and specifically noted that it had not considered the broader issue of cell tower data dumps.

From the Supreme Court judgment: “We do not express a view on matters not before us: real-time CSLI or ‘tower dumps’ (a download of information on all the devices that connected to a particular cell site during a particular interval). We do not disturb the application of Smith and Miller or call into question conventional surveillance techniques and tools, such as security cameras. Nor do we address other business records that might incidentally reveal location information.”

The federal district judge in this Walker case – Louise Flanagan – referenced this part of the decision [PDF] and did make a judgment, that the tower dumps did not equate to an unreasonable search. The police requested information for “a particular place at a limited time,” she noted while Carpenter had been “targeted for an extended time, chronicling that individual’s private life for days.”

Critical response

Instead, the judge argued, the tower dump was “more akin to ‘conventional surveillance techniques’ and tools, such as security cameras and fingerprint collections.”

And, as such, the “privacy concerns underpinning the court’s holding in Carpenter do not come into play here, where the search for data focuses not on ‘the whole of [an individual’s] physical movements’ but rather on the data that was left behind at a particular time and place.”

This case may become a crucial one in that it fills in a critical gap that the Supreme Court identified and refused to decide on: what are the legal protections people can expect when it comes to them being in a specific place at a specific time.

The implications are potentially enormous, especially given the weeks of protests that have taken place in the US.

The truth is that the Supreme Court will likely rule that cell tower data is not protected by the Fourth Amendment if such a case appeared in front of it. The Carpenter decision was 5-4 and there was reason that the opinion specifically mentioned it did not cover tower dumps.

But this case is, we believe, the first to specifically state that tower dumps can be gathered and used without a warrant. And that is a critical point of clarity in a world where everyone carries their phones around with them. ®

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