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Study Finds Cell Phone Location Data May Not Be Accurate

Young woman using cell phone to send text message on social network at night. Closeup of hands with computer laptop in background
By Christopher Coble, Esq. on September 17, 2019 3:03 PM

Drug-sniffing dogs. Hair analysis. Bite-marks, footwear, and ballistics relating to firearms and projectiles. Even some fingerprint tests. The list of once-unassailable, now-debunked forensic evidence is long. And growing.

Cell-Site Location Information, or CSLI, is data compiled based on where your cell phone is when it "pings" towers to receive phone and data signals. The use of CSLI in criminal prosecutions has become so pervasive (and the data available to law enforcement so expansive) that the Supreme Court recently ruled that officers need a warrant to obtain location data from phone carriers. But new research shows that pinpointing a person's whereabouts based on these pings is far from infallible .

So, what happens if faulty forensic evidence like CSLI has been used in your criminal conviction?

Can You Find Me Now?

As reported by The Guardian, some software that converts raw data from cell towers (or masts, as they're referred to overseas) into explainable court evidence contains quite a few glitches :

Among the errors police have discovered is a tendency for the system to omit some data during the conversion process, meaning only selected calls are registered and the picture of the phone's location is materially incomplete.
The system has also linked phones to the wrong masts, connected them to several towers at once, sometimes hundreds of kilometres apart, recorded the origins of text messages incorrectly and got the location of specific towers wrong.

Those revelations have led Danish authorities to release 32 prisoners who'd been convicted using CSLI evidence and put another 40 pending cases on hold. "This is a very, very serious issue," Denmark's director of public prosecutions told the country's state broadcaster DR. "We simply cannot live with the idea that information that isn’t accurate could send people to prison."

Jakob Willer, of the Denmark's telecoms industry association, said the problem stems from the difference between what companies use to facilitate communication between users and what law enforcement officials want to present as evidence. "We should remember: data is created to help deliver telecom services, not to control citizens or for surveillance," Willer said.

Knock, Knock

If you're wondering if the same problems could occur in the United States, we may already have your answer. Three years ago, a Kansas couple sued an IP address mapping company based in Massachusetts after they "were repeatedly awakened from their sleep or disturbed from their daily activities by local, state or federal officials looking for a runaway child or a missing person, or evidence of a computer fraud, or call of an attempted suicide."

According to reports, a mapping glitch from MaxMind defaulted to Theresa and James Arnold's rural home, meaning cops looking for a criminal's IP address frequently found their way to the Arnold residence. "The Arnold family was accused by police and Internet vigilantes of hacking people's email, stealing identities, committing tax fraud, harassing people, and stealing bitcoin," according to Kashmir Hill, who, with the help of security researcher Dave Maynor, uncovered the glitch.

While American law enforcement may not be relying on the same software as their Danish counterparts, cases like the Arnolds' indicate that data obtained on cell and computer location may be called into question when it's presented in court. If you have been charged with or convicted of a crime based on cell phone location data, make sure you talk to an experienced criminal defense attorney who can best assess the validity of that evidence.

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