Ride the Lightning

Mobile Phone Tracking: Junk Science?

June 26, 2013

The ABA Journal recently reported on a case in which testimony about mobile phone tracking was found not to be reliable. The judge even wrote that the FBI special agent's "chosen methodology has received no scrutiny outside the law enforcement community."

It is actually surprising that defense lawyers have long "laid down and taken" prosecutors' assurances that cell tower evidence is wholly scientific. Of course, these are lawyers, many of whom are notably technophobic and their understanding of the science may have been limited.

Though it makes perfect sense to attack some cell tower tracking evidence as unreliable under Daubert, one doesn't want to overstate the case by tarring and feathering all such evidence with the "junk science" label being put forward by some.

As Professor Edward Imwinkelreid (I can't imagine how many times he has had to spell that name) has noted, cell phone records can tell you whether a person who has denied being in the coverage area of a particular tower at a given time was lying.

In some cases, cell phone triangulation can use three towers to give a reasonably accurate location in urban areas, where there are more towers and a more general location in rural areas.

If the phone has GPS, it can pinpoint a caller's location within about 50 meters. Without it, we are left with the far less precise locating capacities of the cell phone towers. One of the misconceptions referenced by the judge was the notion that cell phones always connect to the tower with the strongest signal. Not necessarily so. Factors that determine which tower a phone will connect to include weather, topography, network congestion, physical obstructions, tower maintenance and whether the phone is used indoors or outdoors.

But don't think this case, where an expert may not have done his homework, is a death knell for cell tower evidence. As the good professor noted, that's "just silly."

Hat tip to Dave Ries.