Approximately 30 hours after Mark Beckner was booked into the Santa Cruz County Jail, he was found dead in his cell. Beckner’s son, Brandon Beckner, and his estate (“Plaintiffs”) filed suit asserting that the County of Santa Clara, correctional officers, and jail personnel were deliberately indifferent to Beckner’s serious medical needs in violation of federal and state law.
Plaintiffs filed a motion to exclude the testimony of Patrick Ennis, M.D., who is one of California Forensic Medical Group (“CFMG”) Defendants’ expert witnesses. CFMG Defendants filed a motion to exclude the testimony of Jeffrey E. Keller, M.D., one of Plaintiffs’ expert witnesses.

Correctional Healthcare Expert Witness
Patrick K. Ennis, M.D. is a general physician and withdrawal specialist working in the field of corrections in Chicago, Illinois.
Emergency Medicine Expert Witness
Jeffrey Ernest Keller, M.D. is an emergency medicine physician licensed to practice in Idaho. He has experience providing direct clinical care to incarcerated patients and supervising medical programs in both jails and prisons.
Discussion by the Court
1. Testimony of CFMG Defendants’ Expert Patrick Ennis, M.D.
CFMG Defendants designated Ennis “to provide expert testimony on the standard of care and actions and inactions of CFMG staff during Beckner’s medical care at the Santa Cruz County Jail.”
However, Plaintiffs argued that (1) Ennis lacked the requisite qualifications to testify to specific standards of care, likely course of treatment in an emergency room, and the likely outcome of those treatments, and (2) Ennis’ opinions are not sufficiently reliable. The Court disagreed. First, Ennis is sufficiently qualified to testify to the proffered topics given his experience working “as an attending physician for the Department of Correctional Health Services/Cermak Health Services of Cook County in Chicago, Illinois since 2017” and as “the Medical Director of the Cermak Health Services of Cook County Opioid Treatment Program since March of 2022,” where he “works with correctional nurses everyday.”
CFMG Defendants pointed out that Ennis’ testimony concerning the likely course of treatment in an emergency room and the outcome of those treatments is offered only in rebuttal to Plaintiffs’ expert Keller’s testimony. The Court found that Ennis’ education, training, credentials, and experience as a medical doctor in a correctional setting qualifies him as an expert to discuss standards of care and to rebut Keller’s testimony. Second, Ennis’ opinions are based upon sufficient facts and data given that Ennis conducted a blind review of the records in forming his opinion. Accordingly, the Court found that his opinions are sufficiently reliable.
2. Testimony of Plaintiffs’ Expert Jeffrey Keller, M.D.
Plaintiffs designated Keller to testify to correctional medical systems and oversight, clinical correctional care, emergency department care services and procedures, and emergency transport.
CFMG Defendants did not challenge Keller’s qualifications as a medical professional in a correctional setting. CFMG Defendants instead argued that: (1) Keller’s opinions that Beckner’s death was preventable and that he suffered unnecessarily are speculative, contradict well-established scientific fact, and, as such, are unreliable and more prejudicial than probative; and (2) Keller’s opinions that any actions or omissions by Defendant CFMG caused any harm to Beckner are speculative and are unsupported by sufficient facts. The Court disagreed with both arguments.
Keller based his opinions on his personal experience as an emergency room physician and his personal experience treating ruptured arteries (though not splanchnic artery ruptures). This is a sufficiently reliable basis for his opinions. Further, Keller’s opinions about Defendant CFMG’s actions are based on the operative complaint, grand jury testimony submitted with the complaint, Beckner’s medical chart, CFMG’s “policies and nursing protocols,” and the testimony of nurse Defendant Sarah Hewett, among other sources. Again, this is a sufficient factual basis for Keller’s opinions in this case. The Court found that Keller’s opinions are sufficiently reliable when coupled with his experience and credentials.
Held
The Court denied both Plaintiffs’ motion to exclude the testimony of Patrick Ennis and Defendants’ motion to exclude the testimony of Jeffrey Keller.
Key Takeaway
Expert opinion testimony is relevant if the knowledge underlying it has a valid connection to the pertinent inquiry. And it is reliable if the knowledge underlying it has a reliable basis in the knowledge and experience of the relevant discipline.
Case Details:
| Case Caption: | Beckner V. County Of Santa Cruz |
| Docket Number: | 5:23cv5032 |
| Court Name: | United States District Court, California Northern |
| Order Date: | March 26, 2026 |
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