Limits Of Cell Phone Location Evidence

3 NG’s in Murder Trials Highlight Limits Of Cell Phone Location Evidence

Appointed public defenders recently secured acquittals in three murder prosecutions involving cell phone location evidence that was central to the State’s theories of guilt.  These defense victories demonstrate the effectiveness of employing a litigation process that can work across the wide range of DNA/forensic science disciplines to identify problems and develop solutions, which in our adversarial system of criminal justice is defined as the defense version of the truth about the weight of the forensic science evidence that a jury will find persuasive.  During his 7 years as the Chief Attorney of the Forensics Division at the Maryland Public Defender, Steve Mercer refined and promoted this process to provide effective litigation support for the defense of indigent clients.  Now, he has returned to private practice and is available to consult about your case involving DNA/forensic science evidence.

Two of the defense wins occurred in separate co-defendant murder trials.  In each case, the prosecution claimed that historic cell site analysis placed the defendants together in a park when a murder occurred.  The problem identified by the defense was that the prosecution was overstating the weight of the cell phone evidence; the cell tower and sector records could not place the cell phones at the scene to the exclusion of any other location within the range of the tower.  Also, a pattern of life analysis for one defendant showed that the location data for his phone was consistent with his regular visits to care for his ill mother, who lived near the park.

In the second co-defendant’s trial, early and often defense discovery demands revealed that police had failed to disclose their use of “Stingray” to surreptitiously track the location of the defendants without first obtaining a warrant.

In an unrelated third murder trial, the prosecution introduced “real-time tracking” (RTT) cell phone date prepared by the FBI’s Cellular Analysis Survey Team (CAST). The prosecution claimed that RTT data could shrink the location of a phone within a cell tower sector to the scene of a murder. The defense obtained full discovery after making early and often discovery requests.  The discovery included documents from the cellular carriers disclaiming the reliability of the RTT generated location information. At trial, the defense cross-examined the FBI agent from CAST to show the limitations of RTT location and how the information could vary per call based on the cellular technology in use (4g vs. 3g).  Also, that cell sectors are designed to overlap to avoid calls dropping; a feature that complicates the refinement of location information.

The process used to identify problems (limitations of accuracy) and solutions (a defense narrative that effectively communicates to the jury these limitations) included 1) early and often discovery requests for all call detail records and related indexes, disclaimers, and protocols in electronic format; 2) making targeted discovery requests based on an assessment of the circumstances where police may have conducted a warrantless search using real-time tracking technology (“Stingray”); 3) analyzing the impact of the wireless technology (3G, 4G, LTE) on the per call variance in location accuracy; 4) conducting a pattern of life analysis; 5) effective use of defense expert resources; and 6) developing pointed, effective cross-examination of prosecution experts, direct exams of lay witnesses, and closing arguments.

Because a solution can’t fix a problem that hasn’t been identified, an effective defense must begin with early and often discovery requests that are tailored to the forensic discipline, technology, carrier, analyst, laboratory, State’s expert witness, and overall circumstances of a case.  This targeted approach to early and often discovery requests and related litigation to compel production of relevant discovery is an essential part of effective litigation to challenge any aspect of DNA/forensic science. A bald request for “everything” doesn’t work effectively; conversely, too much specificity may get you some, but not all discovery.  Also, you can’t overlook an insufficient discovery response or expert disclosure by the prosecution until the 11th hour hoping to exclude the State’s expert.  The objective is to obtain full discovery so that the problem can be identified.  Only then can you begin to develop the solution.  When you don’t first identify the problem, the solution of hiring an expert witness is not a solution to persuading the jury; in fact, it can result in poor fit between the expert and a persuasive theory of defense. The problem in your case may require a specialist, but taking a solution first approach gets you an under-qualified generalist.

This can make the difference between winning and losing your case.  Contact RaquinMercer to talk with Steve Mercer about identifying problems and developing solutions to the DNA/forensic science evidence in your case.