Explaining cell phone connectivity and data entry are not subjects of expert testimony


In the case of United States v Graham [2015 U.S. App. LEXIS 13653], there was an appeal from the district court conviction. The appellants in this case were accused of a number of armed robberies. Among other things, the appellants contended that expert testimony was admitted erroneously as lay testimony which merited a reversal of the conviction. The Court of Appeals examined both the testimonies (one of records custodian at Spritz/Nexel, Jeff Strohm and the other of FBI agent Colin Simons) and held that the district court had not erred on this count of admitting the testimonies of the experts named above as lay testimonies.


The defendants in this case were accused of robbing six business establishments in Baltimore County. After their arrest, the police recovered a couple of cell phones from the vehicle that the accused had used for their robberies. The police requested cell phone GPS data from Spritz/Nexel based on a court order and this data played a major role in proving the location of the accused during the robberies. At the appeal stage, among other grounds, the accused contended that prosecution was avoiding the scrutiny of Rule 702 by passing off expert testimony as lay testimony. In allowing this, so went the argument, the district court had abused its discretion. To examine this claim, the Court of Appeals reviewed the testimonies of Strohm and Simons to ascertain as to whether they had to be scrutinized as expert testimony under Rule 702 of the Federal Rules of Evidence.


There were two lay testimonies (that of Strohm and Simons) that the defendants contended were passed off as expert testimonies at the time of admission of the evidence. The Court first examined the testimony of Strohm. He conveyed to the Court two basic facts: one that a cell phone connects to the cell phone tower which is emitting the strongest signal. Secondly, he testified that there are many other factors which are instrumental in finding out which tower a particular cell phone connects to at any given point. These factors extend beyond mere proximity between the device and the tower to line of sight and call traffic. The district court held that Strohm did not apply any special expertise to inform the jury of these facts. He used the experience of his employment at Spritz/Nexel to explain to the jury that cell tower connectivity was not just a simple matter of proximity. Since there was no need for any expertise, this would fall under the category of lay testimony. The Court of Appeals thus upheld the decision of the district court on this count. The other part of Strohm’s testimony involved him explaining to the jury on the technical aspects of how a call was connected. The Court held that this was beyond that of a testimony under Rule 701 but even then any mistake made by the district court in admitting this evidence was harmless. This was because the technical explanation of the working of a cell phone had no bearing on the jury deciding either way.

With regards to the testimony offered by Agent Simons, the decision was more straightforward. In this case, Agent Simons had used the cell phone data that had been supplied by Spritz/Nexel. His work involved mapping GPS data supplied using software which was available to the public. According to the Court, the district court held correctly that such a job of data entry required minimal technical expertise which would not make the work of Agent Simons come within the ambit of Rule 702 of the Federal Rules of Evidence. Thus the court held that mere data entry would not constitute expertise for the purpose of Rule 702.