Law Enforcement Expert Was Not Allowed to Opine on the Party’s Intent
Posted on January 5, 2026 by Expert Witness Profiler
Plaintiff Deborah Jones-MacDonald brought this civil rights action against Defendants, Harris County Sheriff’s Office (“HCSO”) Deputies Ronaldo Delgado and Charles Ribbe (collectively, “the Deputies”), alleging that she suffered personal injuries as a result of an August 13, 2021 encounter with the Deputies.
Plaintiff sought to exclude the report of the Deputies’ expert, Michael A. Dirden, as “methodologically unsound, legally improper, and factually unreliable.”
Law Enforcement Expert Witness
Michael Antony Dirden began his public service career in 1985 as an officer with the Houston, Texas Police Department (HPD) and served there for three decades in progressive ranks including Executive Assistant Chief of Police and Attorney. During his tenure Dirden was instrumental in establishing collaborative accountability protocols for force and internal investigations with the City of Houston Citizen’s Review Committee and the HPD while leading the Internal Investigations Command and serving as Inspector General for the City of Houston. Dirden also led the Professional Standards and Criminal Investigations Command.
Dirden has worked with the United States Department of Justice, the United States Office of Community Oriented Policing, and the California Department of Justice as a subject matter expert addressing internal affairs and accountability, use of force and officer-involved shootings, and leadership.
He earned a Doctor of Jurisprudence from the South Texas College of Law, a Master’s Degree in Criminal Justice from the Sam Houston State University, and a Bachelor’s Degree in Economics from the University of Texas – Austin.
Discussion by the Court
Dirden opined that “Delgado’s action could be determined to be reasonable.” Whether Delgado was ‘acting reasonably’ is, for all practical purposes, the only issue for the jury in this case to decide. Therefore, the Court held that Dirden’s opinion on this point is inadmissible.
Similarly, Dirden’s opinion that “another reasonable and prudent officer could have acted in the same manner under the same or similar circumstances” is just another way of saying that Dirden believes the Deputies’ actions were reasonable. That is, however, another question for the jury to answer.
Dirden opined “the fact that the use of force result in injury, as alleged in this lawsuit, does not mean that the force was unreasonable or excessive. Nor does the age or race of the subject play a role in determining the reasonableness of the force.” Dirden continued: “Even if it is subsequently determined that the Defendants’ reason for attempting to detain the Plaintiff was in error, it still does not give the Plaintiff the right to resist the detention by assaulting Deputy Delgado.”
These are not merely Dirden’s opinions. These are instructions on the law. Such instructions may come only from the trial court. The Court held that Dirden will not be allowed to instruct the jury on the law through his “expert opinion.”
Some of Dirden’s opinions are unhelpful and speculative. For example, Dirden opined that “Plaintiff was not willing to comply with the Defendants and in fact, escalated the situation.” This is not a subject that requires expert testimony. It is for the jury—and only the jury—to assess the Plaintiff’s and the Deputies’ actions and, to the extent it is necessary, determine any of the parties’ intentions. Experts “may not speculate about a party’s intent.”
Held
The Court granted Plaintiff’s motion to exclude the testimony of Defendants’ expert, Michael Dirden.
Key Takeaway
Experts cannot render conclusions of law or provide opinions on legal issues. It is therefore error to allow expert testimony on whether an officer used unreasonable force. There can be only one spokesman of the law, who of course is the judge.
Case Details:
| Case Caption: | Jones-Macdonald V. Harris County |
| Docket Number: | 4:23cv2871 |
| Court Name: | United States District Court, Texas Southern |
| Order Date: | December 09, 2025 |
