Open Issue: Whether Expert Or Lay Testimony Is Required On The Relationship Of Cell Phones and Cell Towers

Eleventh Circuit notes an open issue concerning "whether a witness who is going to testify" regarding the information obtained and relationship between cell phones, towers "must qualify as an expert"; the trial court erred in allowing the testimony as expert testimony “regarding cell phones, cell phone towers, and the information that can be obtained from their interaction” without qualification of the witness as an expert under FRE 702, in United States v. Harrell, _ F.3d _ (11th Cir. May 14, 2014) (No. 11-15680)

FRE 701 was amended in 2000 to "eliminate the risk that the reliability requirements set forth in Rule 702 will be evaded through the simple expedient of proffering an expert in lay witness clothing." ACN 701 (2000). As the Advisory Committee Note indicated, “The amendment does not distinguish between expert and lay witnesses, but rather between expert and lay testimony. Certainly it is possible for the same witness to provide both lay and expert testimony in a single case.” A recent Eleventh Circuit highlights the possibility that expert or lay testimony may be offered about information obtained from cell phones and cell towers. In noting an open issue, the circuit confirmed that the requirements of the applicable rule must be satisfied to admit the testimony.

Trial Court Proceedings: Detective Cell Phone Testimony

Defendant Dantzle was prosecuted for his role in a conspiracy to rob Walgreens and McDonalds in violation of the Hobbs Act. At trial, a detective testified “about the use of Mr. Dantzle’s cell phone before, during, and after the time of the two robberies. “ The defense objected that the government had failed to qualify the witness as an expert: “They need an expert to explain the purpose of it, the cell towers, how phones pick up signals from the towers. Even if the records are self-authenticating under the rules of evidence, that doesn’t explain to the jury the significance of those.” Harrell, _ F.3d at _.

The detective testified about obtaining “the raw billing data” for the cell phone number connect to the defendant from MetroPCS. The information “included the date, time, duration, and direction (incoming or outgoing) of calls, as well as the cell tower location for the beginning of the call and the one for the end of the call.” The defense objected to the witness testimony about “what happens to a transaction signal when a call is placed from a cell phone.” The trial court allowed the government to establish the detective’s experience:

Detective Jacobs explained that he had previously testified about the location of cell phones and that he personally goes out to observe cell tower locations. The district court asked if the government was tendering him as an expert, and the government responded, “Yes, Your Honor.” The district court, over Mr. Dantzle’s objection, then certified Detective Jacobs as an expert in “this field of the relationship between these [cell] phones, the [cell] towers, and the information that can be obtained from those who are qualified experts.” The district court went on to state, in the jury’s presence, that Detective Jacobs “can express opinions. Only an expert can express opinions.”

Following the district court’s ruling, Detective Jacobs testified about how a cell tower receives a transmission when someone places or receives a call on a cell phone. He stated that “the phone sends out a signal to the nearest, most of the time, the nearest tower,” and that this tower will then call the number the caller is trying to reach. He explained that a cell tower has three sides and that a call will register on the side of the tower where the phone is actually located, although the cell phone is not necessarily right next to the cell tower.

Detective Jacobs also testified that he visited the three cell tower locations that had been “hit” by cell phone number 786-523-1283 and created maps which showed these towers, as well as the Walgreens and McDonald’s which had been robbed. He testified that the cell phone was in this area just prior to the two robberies.

Harrell, _ F.3d at _. Following the defendant's conviction, he challenged on appeal the admission of the detective's testimony "as an expert on the relationship and interaction between cell phones and cell towers without requiring the government to comply with the requirements for expert witness opinion testimony pursuant to Federal Rule of Evidence 702." Harrell, _ F.3d at _.

Eleventh Circuit Review: Noting Open Issue

The Eleventh Circuit agreed that the trial court abused its discretion in admitting the detective's expert testimony “regarding cell phones, cell phone towers, and the information that can be obtained from their interaction.” The circuit rejected the government claim on appeal that the detective could testify as a lay witness since the prosecutor had offered him as an expert witness when asked by the trial court.

Since the government offered the detective as an expert, the government had the burden to "show that the witness 'is qualified to testify competently regarding the matters he intends to address.'” Harrell, _ F.3d at _ (quoting United States v. Frazier, 387 F.3d 1244, 1260 (11th Cir. 2004) (en banc) (internal quotation marks and citation omitted) ("The burden of establishing qualification, reliability, and helpfulness rests on the proponent of the expert opinion, whether the proponent is the plaintiff or the defendant in a civil suit, or the government or the accused in a criminal case."); see also Cook ex rel. Estate of Tessier v. Sheriff of Monroe Cnty., Fla., 402 F.3d 1092, 1107 (11th Cir. 2005) ("the proponent [of expert testimony] must demonstrate that the witness is qualified to testify competently, that his opinions are based on sound methodology, and that his testimony will be helpful to the trier of fact")). The government failed to meet its burden by a preponderance of the evidence.

The circuit concluded that it did not need to resolve "whether a witness who is going to testify as Detective Jacobs did must qualify as an expert." _ F.3d at _ (Compare United States v. Yeley-Davis, 632 F.3d 673, 684 (10th Cir.) ("The agent's testimony concerning how cell phone towers operate constituted expert testimony because it involved specialized knowledge not readily accessible to any ordinary person."), cert. denied, 131 S.Ct. 2172 (2011), with United States v. Feliciano, 300 F. App’x 795, 801 (11th Cir. 2008) (agent’s testimony about cell tower sites and records of cellular calls was not an expert opinion)). The issue therefore remains open.

Finally, the circuit concluded that the error was harmless and reversal of the convictions was not required based on other testimony. As the circuit summarized, "the government presented the testimony of a co-defendant, Daniel Jenkins, who told the jury in specific detail how Mr. Dantzle proposed the first robbery (of the Walgreens) and participated in both robberies, and also identified him as one of the masked men in videos and photographs taken during the robberies." Harrell, _ F.3d at _.


The Harrell case raises the issue whether lay or expert testimony may be used to admit evidence “regarding cell phones, cell phone towers, and the information that can be obtained from their interaction.” Because the government had confirmed it was offering expert testimony at trial, it was obligated to satisfy the requirements of FRE 702 for expert testimony. The government failed to meet its burden. The issue remains for another day whether lay testimony may be used as well.


Photo Description: Cell tower camouflage in a tree.


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