Cell Site Analysis Expert Witness Testimony Allowed

In this murder-for-hire case, the Government hired an expert in cell site analysis to provide testimony.  The Defendant filed a motion to exclude the testimony based on unsound scientific methodology.  The court denied the motion.

Facts: This case (United States v. Walter Porter – United States District Court – Eastern District of Louisiana – February 10th, 2016) involves an alleged murder-for-hire.  In order to prove their case, the Government has hired Federal Bureau of Investigations Special Agent W. Charles Williams as a wireless technology expert witness, specifically in the area of historical site cell analysis.  Williams was previously called (and accepted) as the same type of expert witness in the jury trial of Nemessis Bates, a co-conspirator of Porter.  He testified that phones allegedly owned by Bates and Porter were making or receiving calls in certain geographic areas based on call detail records.  Porter alleges that cell site analysis is scientifically unsound and should be excluded under Daubert.  In addition, Porter asks that Williams’s testimony be excluded under Federal Rule of Evidence 403 because the danger of unfair prejudice outweighs its probative value.

Discussion:  The court first looked at the issue of reliability.  Williams noted in his testimony that when a call is made or received by a cell phone it scans the network and connects to the tower that provides the best signal.   This information is recorded.  Generally, the best signal will come from the closest tower to the location of the cell phone, but this is not always the case.  He did note that the analysis of these records will not determine exactly where the cell phone is located, but will provide a general area.

The judge noted that the Fifth Circuit has upheld lower court opinions on challenges to historical cell site analysis and that the same reasoning from those cases apply to the present one.  Williams has undergone extensive training in his area of expertise and described in detail how cell networks work and how he came to his conclusions.  Porter also argues that Williams relies on a false premise that cell phones always connect to the closest tower at the time the call is made.   The court disagreed, stating that Williams has noted that there are other factors at play when a call connects to a tower.  In addition, any argument on this issue goes to the weight of the testimony, not its admissibility.

The court then moved to the relevancy part of the Daubert challenge.  Porter states that since Williams’s testimony is not reliable, it cannot be used to assist the jury in understanding the evidence.  The court, in essence, has already addressed this by concluding that Williams’s testimony is reliable and would help the jury understand the claims brought by the Government against the Defendant.

Last, Porter argues that, under Rule 403, Porter’s testimony will lead the jury to draw inferences that are unsupported by scientific methods.  The court opined that these arguments fail because Williams’s testimony is reliable and any other arguments against Williams can be brought out in cross-examination.

Held:  The Defendant’s motion to exclude the expert witness testimony of Special Agent W. Charles Williams is denied.