Historical CSLI Must Be Presented Through Expert Testimony Under N.J.R.E. 702

Case: State v. Jule Hannah (N.J. Apr. 16, 2026)  |  Court: Supreme Court of New Jersey  |  Author: Justice Pierre-Louis (unanimous)

1) Introduction

In State v. Hannah, the Supreme Court of New Jersey addressed a recurring evidentiary problem in modern criminal trials: whether a law enforcement lay witness may testify about historical cell site location information (CSLI)—particularly the locations of cell towers to which a phone connected—or whether such testimony must be presented by an expert under N.J.R.E. 702.

The defendant, Jule Hannah, was tried for the murder of Miguel Lopez. The State’s theory was largely circumstantial: Lopez allegedly picked up Hannah in Monroe Township after Hannah’s single-vehicle crash, and the two later ended up in Bridgeton where Lopez was shot and his car crashed into a tree. The State relied on (1) Sprint call detail records (CSLI), (2) DNA evidence linking Hannah to a cigar butt found on the passenger seat, and (3) a recorded call suggesting a third person’s presence.

A central disputed issue was whether the CSLI evidence could be used—directly or by “reasonable inference”—to place Hannah with Lopez along the route and near the homicide. The trial court attempted to allow the detective to testify only as a lay witness and repeatedly instructed the jury that tower connections do not establish a phone’s location. Nonetheless, testimony and closing argument effectively invited the jury to use CSLI to infer location and movement (including that the phone must be “a stone’s throw” from the connected tower).

2) Summary of the Opinion

The Court affirmed the Appellate Division’s reversal and ordered a new trial. It concluded that CSLI is “beyond the ken of the average juror” and that attempting to admit tower-location mapping through a lay witness creates a serious risk of confusion and misuse under N.J.R.E. 403. The Court also emphasized that the State cannot avoid the reliability and “net opinion” constraints applicable to experts (as highlighted in State v. Burney) by presenting CSLI interpretation through a lay witness.

3) Analysis

A. Precedents Cited (and How They Shaped the Decision)

1. Standards of review and the role of limiting instructions

• State v. Allen, State v. Garcia, and State v. Medina: The Court reaffirmed abuse-of-discretion review for evidentiary rulings and the “so wide of the mark” standard for reversal. This framing mattered because the Court ultimately found the CSLI ruling was a “clear error” not cured by instructions.
• Hrymoc v. Ethicon: Recognized that limiting instructions can sometimes cure juror confusion—setting up the contrast with this case, where repeated instructions underscored complexity and did not neutralize the misuse of CSLI.
• State v. Jones and State v. Sanchez-Medina: Cited for the proposition that incomplete, unclear, or conflicting limiting instructions can compound prejudice rather than cure it. The Court used this concept to show how the trial’s multiple CSLI instructions, combined with testimony and summation, created mixed messages.

2. Relevance and the risk of confusion

• State v. Higgs and State v. Buckley: Used to explain relevance as probative value plus materiality under N.J.R.E. 401. The Court’s key move was to note that CSLI is offered precisely to support location inferences—making “CSLI is relevant but you may not use it to locate the phone” an unstable posture likely to confuse jurors.
• N.J.R.E. 403: Although not a “case,” it was a decisive doctrinal lens. The Court treated non-contextualized CSLI as evidence that invites speculative or overconfident inferences, thereby risking that probative value is substantially outweighed by confusion/misleading the jury.

3. The lay/expert boundary

• State v. Sanchez: Anchored the analysis of admissible lay opinion under N.J.R.E. 701.
• State v. McLean and Brindley v. Firemen's Ins. Co.: Provided the limiting principle that lay opinion cannot address matters outside the witness’s “direct ken” and on which jurors are equally competent to conclude.
• State v. Bealor and State v. Johnson: Confirmed lay opinions are permissible for matters of “common knowledge and observation,” which the Court held CSLI interpretation is not.
• Hopkins v. Fox & Lazo Realtors and Wyatt by Caldwell v. Wyatt: Supplied the “esoteric subject” test—expert testimony is required when jurors cannot form a valid conclusion from common experience.
• Wyatt by Caldwell v. Wyatt, Taing v. Braisted, and Morales-Hurtado v. Reinoso: These were the Court’s analogies. Just as brake condition and airbag deployment require expert linkage to causation or engineering design, “tower location” requires expert linkage to what can (and cannot) be inferred about a phone’s location and movement.

4. Reliability constraints on experts—and why the State cannot evade them

• Townsend v. Pierre and Pomerantz Paper Corp. v. New Cmty. Corp.: Reiterated that expert opinions must be grounded in facts/data and that unsupported opinions are inadmissible “net opinions.”
• State v. Burney: The doctrinal center of gravity for this opinion. Burney held CSLI “coverage radius” testimony was an inadmissible net opinion when based only on a “rule of thumb.” In Hannah, the Court reasoned that the detective’s conclusory location implications (and the prosecutor’s “stone’s throw” argument) would have been net opinion if offered by an expert—therefore it cannot be smuggled in via a lay witness to avoid N.J.R.E. 702 and N.J.R.E. 703 constraints.

5. The CSLI-specific authority the Court considered (and partially rejected)

• State v. Earls: Provided background on how cellular networks operate and why CSLI differs from GPS in precision.
• State v. Lunsford: Defined “call detail records,” reflecting the Court’s sensitivity to technical record-interpretation issues in criminal trials.
• United States v. Hill: Quoted for the warning that juries may overestimate CSLI precision; admitting testimony that “overpromises” precision can be an abuse of discretion.
• United States v. Natal: Highly influential on the “expert required” point; it held “testimony on how cell phone towers operate must be offered by an expert witness,” and warned that drawing a line between operational testimony and other tower testimony is “frequently” difficult.
• Cases reflecting the majority approach elsewhere—allowing limited lay mapping or tower-location testimony: United States v. Graham, State v. Boothby, State v. Sinnard, Torrence v. Commonwealth, State v. Blurton (quoting State v. Patton), Burnside v. State, and State v. Wyman. The Court expressly rejected this approach for New Jersey, concluding CSLI’s meaning cannot be understood without the technical context that only a qualified expert should supply.
• Maryland’s contrary approach—requiring expert testimony even to “parlay” call detail records into tower location inferences: State v. Payne and Wilder v. State. The Court’s reasoning aligns closely with Maryland’s insistence that the records contain technical data not readily understandable by laypersons.

6. Procedural doctrines

• DYFS v. M.C. III and State v. A.R.: Addressed invited error/waiver. The Court explained the doctrine did not bar review because defense counsel preserved the objection despite a stipulation-like order, explicitly stating he was not waiving prior objections.

B. Legal Reasoning

1. The Court’s key doctrinal move: “Tower location” is not meaningfully separable from “how towers work”

The trial court attempted a compromise: permit a lay detective to “say what the record says” and plot tower locations, while prohibiting testimony about azimuth, sectors, and direct phone location. The Supreme Court held this line is unworkable in practice and conceptually misleading. CSLI’s evidentiary value is inseparable from the technical mechanics that determine tower selection and the limits of resulting inferences.

2. Why CSLI is “beyond the ken” under N.J.R.E. 702

The Court emphasized that multiple technical variables affect which tower a phone uses—tower characteristics, geography/topography, antenna configuration, environmental conditions, phone features, and network behavior. Without expert testimony explaining these variables, jurors are left with either:

• Overconfidence (e.g., “closest tower” or “stone’s throw” assumptions), or
• Underuse (treating the data as meaningless because it is hedged by limiting instructions).

Either way, the evidence is not being used in a controlled, reliable way that “assists the trier of fact” as Rule 702 demands.

3. N.J.R.E. 403: the “non-contextualized CSLI” problem

The Court’s N.J.R.E. 403 analysis is practical: allowing raw tower-location testimony without the explanatory framework necessary to interpret it predictably increases the likelihood jurors will fill in gaps with “common experience”—precisely the type of intuitive reasoning that CSLI can mislead. The Court viewed the repeated limiting instructions as evidence of complexity and confusion, not as an effective cure.

4. The Burney constraint: the State cannot “lay-witness” its way around net opinion

The opinion has a second, important layer: even if an expert were called, New Jersey’s net-opinion doctrine (as applied in State v. Burney) demands tower-coverage and proximity claims be supported by adequate data (not “rule of thumb” and not conclusory assertions). The Court held it would be perverse to bar unsupported CSLI conclusions from experts while allowing the same unsupported conclusions to reach the jury through a lay detective and prosecutorial argument.

5. Application to the trial record

The Court highlighted concrete moments where the “limited” lay testimony effectively became interpretive CSLI evidence:

• Detective Leyman testified that phone records could provide information on where a suspect “may have been located” at the time of the homicide.
• The questioning linked tower hits to the victim’s route and the defendant’s crash area, inviting movement/path inferences.
• On redirect, the State elicited that the phone was hitting tower 37 “before, during and immediately after the homicide.”
• In summation, the prosecutor argued proximity (“stone’s throw”) and movement (“clearly moving with the victim”).

These components, taken together, created the very location inference the trial court purported to prohibit, while denying the jury the technical basis to evaluate the strength and limitations of that inference.

C. Impact

1. Bright-line requirement in New Jersey criminal trials

Hannah establishes a clear New Jersey rule: CSLI “must be presented by an expert witness.” The Court did not endorse the common out-of-state compromise that allows “limited” lay testimony to identify tower locations from carrier records. The foreseeable effect is to standardize CSLI presentation as expert evidence subject to pretrial vetting and cross-examination on methodology, assumptions, and limitations.

2. Reinforced gatekeeping and stronger methodological demands

The decision pressures parties (especially the State) to ensure CSLI experts can explain:

• what inferences CSLI does and does not support (general area vs. pinpoint),
• the variables affecting tower selection, and
• any claimed coverage estimates using objective data (consistent with State v. Burney).

It also equips trial courts to exclude CSLI opinions that “overpromise” precision (echoing United States v. Hill) and to scrutinize closing arguments that convert CSLI into false certainty.

3. Litigation consequences

• Prosecutors must retain qualified experts and avoid “common sense” proximity arguments unsupported by data.
• Defense counsel gains a stronger basis to demand hearings on qualifications and methodology, and to exclude or limit CSLI testimony as net opinion.
• Trial judges can no longer rely on repeated limiting instructions to salvage CSLI admitted without expert context; the Court treated repeated instructions as a warning sign of confusion.

4) Complex Concepts Simplified

• CSLI (Cell Site Location Information): Historical records showing which cell site (tower/sector) carried a phone’s call/text at a given time. It generally indicates a general area, not an exact spot.
• Cell tower “coverage” is not a circle on a map: Which tower a phone uses depends on many factors (terrain, antenna configuration, network load, phone hardware), so “closest tower” assumptions can be wrong.
• Lay vs. expert testimony (N.J.R.E. 701 vs. 702): Lay opinions are limited to matters ordinary people can reliably infer. Expert testimony is required when technical knowledge is needed to help the jury interpret evidence.
• Net opinion (N.J.R.E. 703 / case law): An expert conclusion must be backed by data and methodology. A bare conclusion—like a radius estimate or proximity claim without supporting measurements or tower-specific data—is inadmissible.
• N.J.R.E. 403 “confusing or misleading” risk: Even relevant evidence can be excluded if it is likely to mislead jurors into giving it more certainty than it deserves.
• Azimuth / sectors: Towers often have multiple directional antennas (“sectors”). Understanding directionality is part of interpreting what a tower connection might imply—one reason the Court deemed CSLI technical.

5) Conclusion

State v. Hannah creates an important New Jersey evidentiary rule: historical CSLI is technical, specialized evidence that must be presented through expert testimony under N.J.R.E. 702. The Court’s reasoning is driven by two core concerns: (1) jurors are likely to misunderstand CSLI without technical context, creating N.J.R.E. 403 confusion and prejudice; and (2) the State cannot evade the reliability constraints that govern experts—especially the net-opinion limits emphasized in State v. Burney—by presenting CSLI interpretation through a lay witness.

Going forward, Hannah will reshape how prosecutors and defense attorneys litigate location evidence in New Jersey: CSLI will be treated as expert-dependent proof, and courts will be expected to police both the admissibility of CSLI opinions and the rhetoric used to translate CSLI into claims about where a defendant was and how a phone moved.