This litigation arises from a motor vehicle accident that occurred during the early morning hours of May 10, 2023, on Interstate 20 in Bienville Parish, Louisiana. Ja’Vel Coleman alleged that she sustained injuries when her vehicle struck the rear of a tractor-trailer operated by Saint Fleur.
According to Defendants, Saint Fleur experienced mechanical issues with his tractor-trailer and pulled onto the shoulder of Interstate 20 prior to the collision.
During discovery, Defendants retained Dr. Douglas C. Brown and Josh Lorencz.
Brown examined Coleman on January 15, 2026, and subsequently issued an expert report setting forth his findings and opinions while Lorencz reviewed AT&T Call Detail Records and identified calls and text messages associated with the phone number, the times of those communications, and the cell towers used during those communications.
Coleman sought to exclude, or alternatively limit, the testimony of Dr. Douglas C. Brown and Josh Lorencz under Federal Rule of Evidence 702 and the Daubert standard.
Orthopedic Surgery Expert Witness
Dr. Douglas Coleman Brown has been in private practice in North Louisiana since 1977 and is certified by the American Board of Orthopaedic Surgery and the American Board of Independent Medical Examiners. He also is a member of the American Orthopaedic Foot and Ankle Society.
Digital Forensics Expert Witness
Josh Lorencz possesses substantial training and experience in the field of cell phone forensics. He spent approximately sixteen years with the Simi Valley Police Department working as a detective and police officer and then subsequently worked in digital forensics for Envista Forensics before joining Rimkus.
Lorencz has several certifications in digital forensics and has performed numerous digital analyses of this kind.
Discussion by the Court
I. Douglas Brown
a. Future Medical Costs
Coleman first sought exclusion of Brown’s opinions regarding future medical costs. In their opposition, Defendants expressly stipulate that Brown will not testify or offer opinions regarding Coleman’s future medical costs and represent that they have retained a separate expert to address those issues.
b. Coleman’s Neurological Condition and the October 2023 EMG
Coleman challenged Brown’s opinions regarding Coleman’s neurological condition, arguing that Brown failed to adequately account for an October 2023 EMG report showing radial neuropathy and performed an insufficient neurological examination.
The Court found that these criticisms go to the weight of Brown’s testimony rather than its admissibility. Brown acknowledged the EMG findings during his deposition and provided an explanation for why the study did not alter his clinical conclusions during his January 2026 examination.
Coleman has not demonstrated that Brown employed an unreliable methodology such that exclusion is warranted under Rule 702. Any alleged shortcomings in Brown’s review of the medical records, interpretation of the EMG, or physical examination may be explored through cross-examination.
c. Return to Work
Coleman also sought exclusion of Brown’s opinion that Coleman is capable of returning to her pre-injury sedentary occupation to the extent that opinion relies upon his neurological findings. Because the Court found that Coleman has not established a basis for excluding Brown’s neurological opinions, the Court likewise declined to exclude his opinions regarding Coleman’s functional capacity and work restrictions.
d. Future Treatment
Coleman next sought to exclude Brown’s opinions regarding future surgical treatment and the appropriate surgical approach to Coleman’s anticipated hip arthroplasty. Coleman emphasizes that Brown no longer performs orthopedic surgery and testified regarding certain physical limitations.
The Court found no basis for exclusion of this testimony. The record reflects that Brown is a board-certified orthopedic surgeon who practiced orthopedic surgery for decades, performed the type of procedures at issue during his career, remains licensed, and continues to practice medicine and perform independent medical examinations.
Any reduction in his surgical practice or disagreement regarding the appropriate surgical approach affects the weight of his testimony rather than its admissibility.
II. Josh Lorencz
a. Qualifications
Based upon Lorencz’s education, training, and professional experience, the Court found that he possesses sufficient qualifications to testify regarding cell site location analysis. Accordingly, the Court found that Lorencz is qualified to offer expert testimony in this matter.
b. Reliability of Methodology
Coleman argued that Lorencz’s opinions should be excluded because his CellHawk training occurred in 2016, he has not attended refresher courses since that time, and he cannot explain the software’s internal processes.
Notably, Coleman did not challenge the general reliability of cell site location analysis itself. Instead, Coleman argued that Lorencz lacked sufficient familiarity with the CellHawk software because he has not received recent training and cannot explain the software’s internal processes.
Here, the record reflected that Lorencz has extensive experience utilizing CellHawk and performing cell site location analyses. The fact that he cannot explain the software’s back-end functionality did not render his methodology unreliable.
Any alleged deficiencies in Lorencz’s familiarity with CellHawk’s internal workings can be scrutinized on cross-examination and affect the weight of his testimony rather than its admissibility. Accordingly, the Court rejected Coleman’s argument that Lorencz’s opinions should be excluded based upon his training history or inability to explain CellHawk’s internal processes.
Coleman also argued that Lorencz failed to reliably apply his methodology because he did not independently verify cell tower locations. During his deposition, Lorencz acknowledged that he has independently verified tower locations in prior matters but did not do so in this case. Instead, he relied upon the AT&T records and CellHawk’s mapping functions.
The Court found that this criticism goes to the weight of Lorencz’s testimony rather than its admissibility.
Although Lorencz acknowledged that independent verification through tools like Google Earth may be used to ensure accuracy of the cell tower locations, Coleman has identified no authority finding that such verification is a prerequisite to admissibility under Rule 702.
Likewise, the Court is aware of no authority suggesting that an expert’s failure to employ every available validation technique renders an otherwise reliable methodology inadmissible. The Court concluded that Lorencz’s decision not to independently verify the tower locations presents an issue appropriately explored through cross-examination.
c. Scope of Permissible Testimony
Lorencz was retained to analyze AT&T Call Detail Records associated with a particular telephone number. His report identifies calls and text messages, the timing of those communications, and the cell towers associated with those communications. The record further reflects that Lorencz reviewed the AT&T Call Detail Records and the Louisiana Uniform Crash Report but did not review GPS data, electronic logging device (“ELD”) data, or other location-specific information.
Lorencz testified that cell site location analysis did not permit him to determine the precise GPS location of a device. Rather, he can only identify the tower and sector utilized during a communication.
Thus, the fact that a communication utilized a specific tower only indicates that the device was within the serviceable range of that tower at that time; it does not establish the device’s precise location.
Accordingly, Lorencz may testify regarding the contents of the AT&T Call Detail Records, the timing of the calls and text messages reflected therein, the cell towers and sectors associated with those communications, and the general principles underlying cell site location analysis. Such testimony may assist the jury in understanding the evidence.
However, the Court finds that the methodology employed by Lorencz does not support testimony concerning the precise location of any vehicle or person, the precise time that Saint Fleur arrived at the accident location, the length of time that any vehicle remained at a particular location, or other conclusions that cannot be reliably derived from the Call Detail Records.
Likewise, Lorencz may not offer opinions regarding user identity, driver behavior, distraction, causation, or matters beyond the scope of his report and expertise.
Held
The Court granted in part and denied in part Coleman’s Daubert motions to exclude and/or limit the testimony of Dr. Douglas Brown and Josh Lorencz.
Key Takeaway
Experts routinely rely upon specialized software tools without possessing detailed knowledge of the software’s source code or internal algorithms.
However, Rule 702 requires not only that expert testimony be reliable, but also that it assist the trier of fact. Thus, even where an expert is qualified and employs a reliable methodology, the testimony must remain within the bounds of what that methodology can reasonably support.
Case Details:
| Case Caption: | Coleman v. Burlington Ins. Co. |
| Docket Number: | 5:24cv512 |
| Court Name: | United States District Court, Louisiana Western |
| Order Date: | July 13, 2026 |
