Cell Tower Records and Tarot Cards
You got a methodology in there somewhere?
I have been fortunate enough to be an expert witness in a few cases involving cell tower evidence, where the prosecution attempts to place a defendant at a crime scene based on records from their mobile operator. Most start out the same way:
- The defense attorneys send me a law enforcement evidence report with some maps purporting to show cellphone activity.
- I make my initial review of the report and tell them, “It doesn’t really say anything about where the phones were.”
- They say, “That’s what we thought, too, but since we aren’t experts, we couldn’t be sure.”
In my first article on cell tower evidence, I gave some commentary about the weakness of the “nearest-cell” methodology typically used by law enforcement. What I usually find in practice, though, is no methodology at all, just a map presenting the raw records, with no analysis and no conclusions. The preface to the report may define a nearest-cell kind of methodology, apparently unused, and if the defense challenges the law enforcement expert on the accuracy of the report, he/she will probably give a figure north of 95%. None of it adds up to anything that makes sense.