State v. Hannah

Amicus brief arguing that the state needs expert witnesses to explain to juries the limits of using cell phone towers to locate suspects at crime scenes.

At trial, the state attempted to use the fact that defendant’s cell phone “pinged” certain cell towers to prove that the defendant was a passenger in a car in the moments leading up to a crime. The state had a lay law enforcement officer testify about how this cell phone tower evidence indicated the defendant’s location. We filed a joint amicus brief with the Innocence Project arguing that the trial court made a mistake by allowing a lay witness to present this technically complex evidence and explaining the evidentiary standards required for prosecutors to introduce cell site location information as evidence of a defendant’s location during a crime. The brief points out the highly technical nature of this information, arguing that (1) scientific expertise and data is essential to ensuring the accuracy and reliability of testimony and (2) by not providing an expert, the state deprived Mr. Hannah of his constitutional right to meaningfully cross examine the evidence used against him.