Expert Witness Profiler

Category: Law Enforcement Expert Witness

Law Enforcement Expert’s Testimony on the Unique Overdose Risk of Fentanyl Excluded

David James Michael Jensen is charged in an eight-count Superseding Indictment with five counts of Unlawful Possession of a Firearm, one count of Possession of Controlled Substances with Intent to Distribute (methamphetamine and fentanyl), one count of Carrying a Firearm During and in Relation to a Drug Trafficking Crime, and one count of Possession of Fentanyl with Intent to Distribute for events that occurred on five separate dates.

The Government provided Jensen’s counsel with notice of potential expert testimony by Homeland Security Investigations Supervisory Special Agent Marco Dkane about criminal practices with respect to drugs and guns to be presented at trial.

Jensen filed a motion requesting the exclusion of testimony from Dkane about common methods and practices of drug dealers.

Law Enforcement Expert Witness

Agent Marco Dkane is a twenty-two year veteran of Homeland Security Investigations (“HSI”) with the United States Department of Homeland Security.

His duties as a supervisory special agent include serving as Task Force Commander of a High Intensity Drug Trafficking Area Task Force, supervising investigative activities of narcotics agents and detectives from numerous agencies, instructing HSI investigators in narcotics investigations, and serving as a witness relating to drug trafficking method and trends. His investigative duties include conducting investigations of fentanyl, counterfeit pharmaceuticals, heroin, methamphetamine, cocaine, and MDMA (ecstasy) trafficking.

He has also served as an instructor for both local and national law enforcement training on counterfeit medications, contraband/narcotics, investigative techniques, and Organized Crime Drug Enforcement Task Forces. Dkane has been involved in the investigation of transnational criminal organizations and drug trafficking organizations. He has served as an expert witness in jury trials where his testimony included explaining the practices of drug traffickers.

Fortify your strategy by reviewing a Challenge Study detailing grounds for excluding Marco Dkane’s expert testimony.

Discussion by the Court

Rule 702 Challenge

1. Relevance

a. General Relevance Challenge

Jensen challenged the expert testimony proffered by the Government because he asserted that this case involved no complex illegal activities that require expert guidance. However, the Ninth Circuit has repeatedly allowed expert testimony regarding modus operandi in cases where defendants have been charged with possession with intent to distribute drugs or possession of a firearm in furtherance of a drug trafficking crime, as Jensen is charged in this case.

The Court found that Dkane’s testimony is generally relevant and will help the jury understand the evidence or determine a fact in issue.

b. Specific Relevance Challenges

(1) Matters of “Common Knowledge” to Jurors

Jensen asserted that parts of Dkane’s proffered opinions are “matters of common knowledge familiar to jurors,” “at least for those who have read a newspaper, seen a movie, or watched television since 1960 or so.”

In this case, the Government proffered that Dkane will testify about the difference between distribution and user amounts of drugs and provide other details relevant to the distribution counts.

During a search incident to arrest on April 7, 2022, officers found over $1,000 in low-denomination bills on Jensen, and a search of his vehicle found weapons and a safe containing 528 fentanyl pills, 75 grams of methamphetamine, and 22 grams of heroin in the trunk of a vehicle he had accessed moments earlier. The Government asserted that the jury is entitled to hear Dkane’s opinion as to, for example, whether 400 pills is a distributor’s or user’s quantity of fentanyl possession, information that is beyond the common knowledge of most individuals. The Court agreed that this type of information “supplements lay understandings about drug dealing and is a far cry from what is commonly known.”

(2) Types of Controlled Substances and Drug Use

Jensen asserted that the proffered opinion regarding the types of controlled substances largely consists of facts that “are both unassailable and immaterial to any issue in the case. . . . Fascinating, I suppose, in a Discovery Channel documentary way, but wholly unconnected with the facts of this case.” The Government responded that Jensen’s argument ignored the fact that he was found with the drugs that will be discussed by Dkane during the charged events. Some background testimony will be admissible to provide context to the Government’s case and may also help explain distributor’s or user’s quantity of the drugs. The Court found that testimony about types of controlled substances and how drugs are used is relevant.

However, the Court agreed with Jensen that Dkane’s testimony regarding harm to users or society generally, such as the unique overdose risk of fentanyl, is not relevant.

(3) Common Slang Terms

Jensen asserted that Dkane’s testimony regarding common slang terms and codes for controlled substances is unnecessary as none of the words at issue are uttered in this case. The Government acknowledged that this testimony is likely unnecessary in this case and it does not plan to introduce this testimony. The Court agreed that this testimony seems irrelevant in this case.

(4) Legal Opinions

Jensen asserted that certain opinions—such as whether fentanyl is a controlled substance—call for a legal conclusion that is for the Court and not the jury.

The Government responded that ” Dkane’s testimony that various drugs are controlled substances, while containing within it a legal conclusion, is obviously necessary as a predicate fact to explain why drug dealers do or not do certain things.” The Court agreed with the Government. Further, it appeared that Jensen is not contesting that the drugs at issue in this case are controlled substances under federal law as he has agreed to a jury instruction on to this effect.

(5) Testimony Regarding “In Furtherance Requirement”

Jensen asserted that admission of expert testimony on whether a firearm was possessed in furtherance of the charged drug trafficking would violate Rule 702.

However, the Government will not be relying solely on the expert testimony to establish that Defendant possessed a firearm in furtherance of a drug trafficking crime, but also intended to introduce evidence of the proximity, accessibility, and location of the firearms in relation to the locus of the drug activities.

2. Reliability

As a preliminary matter, the Court noted that Jensen did not challenge Dkane’s qualifications as an expert, nor did he dispute that Dkane has specialized knowledge on the topics of types of controlled substances or common characteristics of drug trafficking or drug traffickers and has based his opinions on that knowledge.

The Court found that the combined aspects of Dkane’s background, training and experience clearly meet the requirements of Federal Rule of Evidence 702 and qualify him to testify as an expert in the field of drug trafficking generally based upon his knowledge, skill, experience, training, and education.

Rule 403 Challenge

1. General Prejudice

Jensen asserted that “[g]eneral expert testimony regarding common methods and practices of drug dealers should be excluded because it gives rise to unfair prejudicial inferences that outweigh the limited probative value of the evidence.” While the Court is cognizant of the dangers raised by Jensen, the risk that unfair prejudice will actually materialize is not so high that it substantially outweighs the probative value of Dkane’s testimony.

2. Specific Prejudice

a. Comment on a Defendant’s Mental State

Jensen correctly asserted that a witness is not allowed to state an expert opinion or inference about whether the Defendant did or did not have a mental state or condition that constitutes an element of the crime charged.

Therefore, the Court granted Jensen’s motion but only as to excluding testimony by an expert as to whether the Defendant did or did not have a mental state or condition that constitutes an element of the crime charged.

b. Fentanyl addiction and deaths

Jensen argued that Dkane’s testimony concerning the addictive nature of fentanyl, the deaths it has caused, and the societal devastation resulting from its use did not prove the elements of the charged offense and created a substantial risk of prejudice.

The Court agreed that testimony regarding fentanyl statistics or death toll would be more prejudicial than probative and will exclude such testimony.

The Court will limit the Government to eliciting testimony on the dangers of fentanyl as related to drug trafficking practices and as explanatory information related to law enforcement’s handling of the investigation and the seized drugs.

c. Testimony regarding types of controlled substances

Jensen asserted that evidence about where the overwhelming majority of drugs trafficked in Washington are made, the fact that the drugs are usually smuggled into the United States through states other than Washington, and how they are transported to other localities are “wholly unconnected with the facts of this case.” The Court agreed that this type of evidence, while perhaps marginally relevant, is ultimately more prejudicial than probative.

Therefore, the Court granted Jensen’s request to exclude this type of testimony pursuant to Rule 403.

Held

The Court granted in part and denied in part the Defendant’s motion to exclude the testimony from Marco Dkane.

Key Takeaway:

An expert’s opinion may overlap with the jurors’ own experiences or cover matters that are within the average juror’s comprehension, so long as the expert uses some kind of specialized knowledge to place the litigated events into context. Therefore, Dkane’s testimony about the difference between distribution and user amounts of drugs and other details relevant to the distribution is relevant.

Case Details:

Case Caption: United States V. Jensen

Docket Number: 2:24cr204

Court Name: United States District Court, Washington Western

Order Date: August 28, 2025

September 2, 2025
Law Enforcement Expert’s Testimony Regarding the Standard of Care in an Involuntary Detention Setting Admitted

This case arises out of Plaintiff Gregory Palm’s claim that he received deficient medical care while incarcerated in the Jones County Jail and Baldwin County Detention Center.

Sheriff Butch Reese, Captain Shane Moody, Lieutenant Brent Skinner, and Lieutenant Dalton Hart (hereinafter “Defendants”) disclosed Kathryn Wild and Paul Cappitelli as expert witnesses. Plaintiff Gregory Palm filed a motion to exclude the testimony of these witnesses.

Nursing Expert Witness

Kathryn Jean Wild has extensive experience working alongside, supervising, and training correctional officers regarding their responsibilities and duties as they relate to the provision of healthcare in a correctional facility.

Wild is a registered nurse with a bachelor’s degree in health services management and a master’s in public administration. She has worked in the field of correctional healthcare for forty years and has been certified as a correctional healthcare professional since 1991.

Get the full story on challenges to Kathryn Wild’s expert opinions and testimony with an in-depth Challenge Study.

Law Enforcement Expert Witness

Paul A. Cappitelli is a career law enforcement officer with extensive experience working in administration, patrol, custody, homicide investigation, public affairs, and gang enforcement.

Want to know more about the challenges Paul Cappitelli has faced? Get the full details with our Challenge Study report.

Discussion by the Court

Expert Testimony of Kathryn Wild

Palm asserted that Wild is not qualified to opine about the conduct of jail correctional officers because she is a nurse and not a correctional officer herself.

Wild is a registered nurse who has worked in the correctional healthcare setting for nearly forty years. She worked as a nurse in five correctional facilities, then went on to serve as the health services administrator for San Bernardino County, California, and the deputy agency director for correctional health services for Orange County, California. In her supervisory roles for San Bernardino County and Orange County, she was responsible for the oversight and training of non-medical staff such as corrections officers regarding the provision of healthcare services and she developed and implemented the healthcare policies that governed correctional facility employees.

She now operates a consulting business in which she assists in training correctional facility staff, including correctional officers, on their responsibilities relating to the provision of healthcare for inmates and detainees.

The Court found that Wild is qualified to opine on the conduct of correctional officers in this action. While she may not be a correctional officer, Wild is familiar with (and has even participated in the creation of) standards governing the involvement of correctional officers in the provision of healthcare to detained individuals. She has first-hand experience training such officers on how they should provide healthcare to those in their custody. Wild’s knowledge and experience concerning the standards for correctional officers’ responsibilities relating to healthcare rendered her qualified to offer expert testimony in this action.

Having found that Wild was qualified to provide expert testimony on the subjects explained hereinabove, the Court found unpersuasive Palm’s argument that Wild’s testimony would be unreliable and unhelpful to the trier of fact.

Expert Testimony of Paul Cappitelli

Palm argued that Paul Cappitelli’s testimony should be excluded because it will not help the trier of fact understand the evidence or determine a fact at issue.

Cappitelli is a career law enforcement officer who opines that the jail staff in this action “were attentive and conscientious in their interactions with Palm” and “arranged for [Palm] to receive medical treatment” when they first noticed his need for medical attention, such that he was never denied medical care.

He also opined that Palm was properly monitored during his incarceration in conditions that were adequate, and that there is no evidence that any policy or practice could have altered Palm’s health outcome.

Cappitelli asserted that the jail staff were adequately trained and not responsible for medical care decisions. He based these opinions on “the standard of care prevalent in the corrections and custodial profession and facilities, and the practices of corrections personnel in this matter.”

Cappitelli is familiar with the standard of care unique to the corrections environment because he has extensive experience “personally supervis[ing] numerous officers and professional staff support employees in a custody environment.”

In summary, the Court held that Cappitelli’s expert testimony regarding the standard of care in an involuntary detention setting, and whether the Defendants met that standard of care under the circumstances in this action, will assist the trier of fact.

Held

The Court denied Palm’s motion to exclude the testimony of Defendants’ expert witnesses, Kathryn Wild and Paul Cappitelli.

Key Takeaway:

Monitoring detainees or prisoners in a correctional environment is distinct from monitoring someone in the home or office in a way that average jurors may be familiar with. That unique setting carries with it a unique standard of care which the average layperson will likely need expert assistance to understand.

Cappitelli’s testimony about the standard of care applicable to custodial officers in an involuntary detention setting goes beyond “what lawyers for the parties can argue in closing arguments.” As long as Cappitelli connects his conclusions and opinions to the unique standard of care and special circumstances in the detention setting, they may be helpful to the jury.

Case Details:

Case Caption: Palm V. Corrcare Inc Et Al

Docket Number: 3:24cv47

Court Name: United States District Court, Georgia Middle

Order Date August 11, 2025

August 13, 2025
Law Enforcement Expert Was Not Allowed to Opine on the Existence of Probable Cause

This matter arises from Plaintiff Gina Kuhlman’s arrest by Officers David Grasha and Samantha Haggerty of the Cleveland Division of Police, for operating a motor vehicle under the influence (“OVI”) and for refusing to submit to a drug and alcohol test.

To support her case, Kuhlman offered the expert reports of Rajeve Saini and Timothy A. Dimoff. Defendants filed a motion to disqualify the Plaintiff’s experts, Dimoff and Saini.

Law Enforcement Expert Witness

Timothy A. Dimoff has over 40 years of experience in law enforcement procedures, high-risk security issues and private security procedures.

Dimoff graduated from Denison University with a B.A. in Sociology with an emphasis in Criminology. After finishing the police academy, Dimoff served as a patrol officer with the Akron Police Department (“APD”) for approximately two years. During that training period, he obtained “on-the-job training” from a “field training officer” in investigating suspects for driving under the influence.

Following his two (2) years on patrol, Dimoff was “handpicked from the entire department” to be an officer in APD’s “Special Crimes Unit” investigating “higher level types of crimes,” which also required him to be a S.W.A.T. response officer.

Get the full story on challenges to Timothy Dimoff’s expert opinions and testimony with an in-depth Challenge Study.

Phlebotomy Expert Witness

Rajeve Saini is the owner of Advanced Medical Services, the company who performed a drug and alcohol screen for Plaintiff at her request on the day after her arrest. He was trained as a phlebotomist and ultimately became certified as a Paramedical Examiner.

He and his company are certified and recognized by the Federal Motor Carrier Safety Administration as Department of Transportation compliant in drug and alcohol collections and training.

Want to know more about the challenges Rajeve Saini has faced? Get the full details with our Challenge Study report.

Discussion by the Court

Timothy Dimoff

Defendants argued that (1) Dimoff lacked specialized knowledge regarding traffic stops or OVI arrests that would help the trier of fact because his only experience with traffic stops and OVI arrests was from “over thirty years ago” and (2) Dimoff’s expert report is predicated upon a flawed methodology.

Analysis

The Court found that Kuhlman has failed to satisfy her burden to show that Dimoff’s testimony is admissible.

First, Kuhlman has not shown what “specialized knowledge” Dimoff possessed that would “help the trier of fact to understand the evidence or to determine a fact in issue” because the determination of whether the Officers had probable cause to arrest Kuhlman is a legal, not a factual issue.

Not only did Dimoff’s testimony demonstrate that he is opining on the ultimate issue or legal conclusion as to whether there was probable cause, but Kuhlman insisted four (4) times in her briefing that the purpose of Dimoff’s expert testimony is to show probable cause.

Therefore, on this basis alone, because Kuhlman exclusively relied on Dimoff’s testimony to establish that probable cause did not exist for the Officers’ arrest of Kuhlman, and because using expert testimony for that purpose is improper, the Court will not consider Dimoff’s testimony.

Second, the Court also agreed with Defendants’ contention that Dimoff’s methodology was insufficient because he failed to consult the Officers’ depositions, Kuhlman’s deposition, Cleveland’s policies and procedures related to the transport of arrestees, or, critically, the bodycam footage of Kuhlman at Chipotle.

Rajeve Saini

Kuhlman claimed that “Saini’s testimony show that on the day after the incident, Plaintiff went into an independent testing lab and gave a urine sample, which provided negative for alcohol and many commonly-ingested drugs.”

Defendants disagreed, arguing that “Saini’s limited testimony as to the test results taken the day after Plaintiff’s arrest is not outside the scope of the knowledge of a juror and is unnecessary for purpose of Rule 702.”

The parties agreed that the test that Saini’s company administered, and the Fairview test results, were negative as to the specific substances tested for. So, that fact is not “in issue.”

And neither is whether Kuhlman actually consumed alcohol or drugs on December 30, 2018, or on December 31, 2018, because the probable cause inquiry turns on what the Officers perceived on the day of the arrest.

It is the Court that must determine the ultimate legal issue of whether the undisputed material evidence demonstrates that the officers had probable cause to arrest Kuhlman. Since Saini’s expert report and deposition testimony offer no assistance in making this determination, the Court concluded that Saini’s expert report and deposition testimony cannot help the trier of fact determine a “fact in issue.”

Held

The Court granted the Defendants’ motion to disqualify the Plaintiff’s experts, Timothy Dimoff and Rajeve Saini.

Key Takeaway:

Dimoff was disqualified as an expert in this case because Kuhlman introduced Dimoff’s testimony for the improper purpose of opining on the existence of probable cause, and because Dimoff did not consult the bodycam footage or depositions in rendering his opinions.

Case Details:

Case Caption: Kuhlman V. City Of Cleveland, Et Al

Docket Number: 1:22cv536

Court Name: United States District Court, Ohio Northern

Order Date: July 21, 2025

July 24, 2025
Law Enforcement Expert’s Testimony on Conspiracy Membership Excluded

The Government charged Xiong Lin with conspiracy to distribute, and to possess with intent to distribute, controlled substances. From approximately May through at least September 2022, Lin allegedly conspired with others—known and unknown—in the District of Massachusetts and elsewhere to distribute cocaine and MDMA.

Government filed a motion in limine to exclude the testimony of Defendant Xiong Lin’s proposed expert witness, Mr. Craig J. Nicewicz.

Lin designated Nicewicz to rebut the Government’s anticipated assertion that anyone performing occasional tasks for drug traffickers necessarily knows the scope of the conspiracy. Nicewicz indicated that he has “conducted comprehensive investigations into law enforcement practices, including surveillance tactics, confidential informant reliability, and search and seizure procedures, with a focus on ensuring that Defendants’ constitutional rights are protected.”

The Government moved to exclude Nicewicz’s testimony on three grounds: (1) Lin’s expert disclosure was untimely and failed to satisfy Rule 16(b)(1)(C); (2) Nicewicz lacked specialized knowledge of drug-trafficking organizations; and (3) his opinions are unreliable and have the potential to confuse the jury.

Law Enforcement Expert Witness

Craig J. Nicewicz worked in an administrative or managerial capacity within the United States District Court for the District of Massachusetts for over twenty years.

When he finally left the Court in 2017, he went on to work as a management analyst for the United States Administrative Office in Washington D.C., where he worked on rewriting nationwide manuals and polices for the U.S. Courts related to staff training and operations within budget constraints. He is currently employed as a private investigator with American Legal Investigative Service.

Want to know more about the challenges Craig Nicewicz has faced? Get the full details with our Challenge Study report.

Discussion by the Court

Lin contended that Nicewicz’s testimony is necessary to ensure a balanced presentation and prevent the jury from being misled about conspiracy membership.

The Government first argued that Lin failed to meet the requirements of Federal Rule of Criminal Procedure 16 because his untimely expert disclosure consisted only of a single-page summary and a curriculum vitae omitting any detailed statement of Nicewicz’s opinions, the data he reviewed, or the analytical steps he employed. It next contended that, even if the disclosure were timely, Nicewicz is unqualified to opine on drug-trafficking organizations. Finally, prosecutors warned that admitting Nicewicz’s testimony—lacking methodological rigor—risks confusing the jury.

Lin conceded that Nicewicz has no specialized training, publications, or peer-reviewed work in the field of narcotics conspiracies and that he only previously testified in a Massachusetts state case as a factual rebuttal witness regarding interviews he conducted. Lin also conceded that Nicewicz has no formal law enforcement training or academic credentials in criminal justice but emphasized his two decades in court administration in the District of Massachusetts and his current work as a private investigator. Nicewicz would not testify about Lin’s specific intent or knowledge, but rather would offer general observations about courier roles in drug cases. Lin maintained that these experiences qualify Nicewicz to challenge the assumption that all couriers knowingly participate in drug conspiracies and that excluding his testimony would permit misleading expert opinions to go unchallenged, risking unfair prejudice.

Analysis

The Court held that Nicewicz’s opinions rest on passive observations rather than on the application of reliable principles to case-specific facts. His curriculum vitae reflects career experience in Court administration, not scientific or technical analysis of criminal networks. Lin has provided no information about the particular facts or data Nicewicz reviewed, nor any detailed outline of analytical steps. His private-investigation work offers no recognized methodology for determining when a courier knows the contents of a delivery. Even if he “observed firsthand countless criminal cases,” that passive experience places him at no greater advantage than the factfinder. Nicewicz’s sole state-court testimony merely rebutted witness statements about interviews he conducted, not membership in a drug conspiracy.

Held

The Court granted the Government’s motion to exclude the testimony of defense expert Craig J. Nicewicz.

Key Takeaway:

Defense expert Nicewicz was retained to challenge the assumption that all couriers knowingly participate in drug conspiracies. Nicewicz’s opinions were based on his extensive experience in the federal court system, particularly in criminal trials conducted in the U.S. District of Massachusetts, and his experience as a private investigator.

However, his private-investigation work offered no recognized methodology for determining when a courier knows the contents of a delivery. Even if he “observed firsthand countless criminal cases,” that passive experience places him at no greater advantage than the factfinder.

Case Details:

Case Caption: United States V. Feng Chen and Xiong Lin

Docket Number: 1:22cr10279

Court Name: United States District Court, Massachusetts

Order Date: July 18, 2025

July 21, 2025
Law Enforcement Expert’s Testimony on Sound Professional Standards Admitted

The Plaintiff, Hannibal Buress, is a well-known stand-up comedian who brought this case against two Miami Police Department (“MPD”) Officers, Luis Verne and Elio Villegas, and the City of Miami, for violations of his civil rights under both federal and Florida law based on an incident in the Wynwood area of Miami on December 9, 2017.

Buress retained Dr. Christopher Chapman as a testifying expert in this case. Chapman opined that “the arrest and handcuffing of Buress on December 9, 2017 . . . was objectively unreasonable and not consistent with police training/standards,” and “consistent with what is commonly referred to as Contempt of Cop.”

Verne believed that Chapman “improperly usurps the jury’s role of evaluating the testimony of the witnesses, making determinations as to the credibility of the witnesses, and applying those facts to the law instructed to them by this Court.”

Law Enforcement Expert Witness

Dr. Christopher Chapman is a retired Sergeant of Police with the Township of Cranford Police Department, Cranford, New Jersey. He has held numerous law enforcement positions and is also an Associate Professor and Founding Director of the Criminal Justice Degree Program at Kinsborough Community College—City University of New York (CUNY), Brooklyn, New York. He earned a PhD. in criminal justice from Northcentral University.

Want to know more about the challenges Christopher Chapman has faced? Get the full details with our Challenge Study report.

Discussion by the Court

Federal Rule of Evidence 702

Verne argued that Chapman will opine on “whether the officers violated constitutional standards,” which “is the function of the jury.”

However, Buress clarified that “before a jury, Chapman will not provide testimony about the existence of probable cause; instead, he will testify about Officer Verne’s procedures and tactics.”

Considering “Chapman’s role is limited to describing sound professional standards and identifying departures from them,” the Court denied Verne’s Daubert motion.

Yet, in Buress’ response to Verne’s Daubert motion, Buress stated that Chapman’s first opinion includes opining that “a reasonable officer in Officer Verne’s position would not have reasonably believed they had the authority to censor Buress’ speech regardless of Officer’s Verne disagreement with the speech.” This toes the line between opining on “sound professional standards and identifying departures from them” on the one hand, and whether Officer Verne did indeed violate state law, on the other. However, the Court ended up giving credit to Buress’ purported limitations on Chapman’s potential testimony.

Federal Rule of Evidence 403

Verne believed Chapman’s testimony was inadmissible under Fed. R. Evid. 403 because “Chapman’s testimony about whether Officer Verne had the legal authority to arrest Plaintiff and whether the constitution was violated would mislead the jury in its function as a factfinder, waste time, and is outweighed by the facts that Buress hopes to prove.” Therefore, to Verne, Chapman’s “legal conclusions . . . would also present cumulative evidence to the extent it is based on any facts.”

However, it is premature to conclude that Chapman’s testimony is inadmissible under Rule 403. To begin with, and as Buress pointed out, Verne failed to “provide citations to specific opinions included in Chapman’s report that would confuse the jury, nor does he explain precisely why his testimony would confuse the jury.”

Additionally, and as the Court noted when denying Verne’s Daubert motion, Buress purports to place limits on Chapman’s testimony that would prevent Chapman from opining on issues that are solely within the province of the jury. Thus, at this time, the Court cannot conclude that Chapman’s testimony would mislead or confuse the jury in a way that substantially outweighs the relevance of his testimony.

Finally, Verne misstated the standard on cumulative evidence when he stated that Chapman “would also present cumulative evidence to the extent it is based on any facts.”

Verne seemed to believe that Rule 403 excludes any cumulative evidence but the Court clarified that Rule 403 only excludes the “needless presentation of cumulative evidence” when the repetitive nature of such evidence “substantially outweigh[s]” its relevance.

Held

The Court denied Luis Verne’s Daubert motion to exclude the testimony of Plaintiff Hannibal Buress’ expert Dr. Christopher Chapman.

Key Takeaway:

A police practices expert may present factors that might inform an officer’s decision regarding standards such as probable cause or the use of force when making arrests.

Case Details:

Case Caption: Buress V. City Of Miami Et Al

Docket Number: 1:20cv23078

Court Name: United States District Court, Florida Southern

Order Date: July 10, 2025

July 11, 2025
Law Enforcement Expert Is Qualified Despite No Direct Experience with Philadelphia Police

Andrew Swainson filed a § 1983 claim against the City of Philadelphia. He challenged his 1989 conviction for Stanley Opher’s murder. He spent more than 30 years in prison. Swainson argued police officers fabricated and concealed key evidence. He said they created a false narrative of his flight to Jamaica. They also used a coerced eyewitness and ignored other suspects.

He claimed the City enabled this misconduct. According to Swainson, officials failed to train, supervise, or discipline detectives. That failure, he said, allowed unconstitutional practices to continue.

Swainson retained Michael K. Lynch as an expert in police practices. Lynch worked in law enforcement for over 30 years. In April 2024, he submitted a report. He reviewed police records, lawsuits, and prior wrongful convictions. Lynch found a pattern of misconduct inside the homicide division dating back to the 1970s.

The City and two detectives filed a motion to exclude Lynch’s report and testimony. They called it irrelevant and unreliable.

Law Enforcement Expert Witness

Michael K. Lynch has 32 years of experience in law enforcement. Since 2013, Lynch has been employed by the Camden County Police Department as assistant chief of police (2013-2014), senior policy advisor (2015-2023), and chief of staff (since 2023). As chief of staff, Lynch assists the chief of police in connection with accounting, human resources, procurement, administrative support services, and police records.

Get the full story on challenges to Michael K. Lynch’s expert opinions and testimony with an in-depth Challenge.

Discussion by the Court

Expert Qualifications

The court found that Michael K. Lynch was qualified to testify as an expert on police practices. Lynch worked in law enforcement for 32 years. He served in leadership roles in the Camden City and Camden County Police Departments. He also completed training at Northwestern University’s School of Staff and Command and the West Point Command and Leadership Program. Lynch investigated violent crimes and supervised misconduct cases. He also developed police policies on investigations, supervision, and training. The court ruled his experience met the expert qualification standard.

Reliability of Methods

The court next considered whether Lynch’s opinions were reliable. Because Lynch is not a scientist, the court looked at his experience and methods. Lynch reviewed police files, lawsuits, public records, and media investigations. He relied on his knowledge of minimally accepted police practices, such as avoiding coercion, fabrication, or suppression of evidence. The court rejected the defense’s claim that Lynch relied only on pleadings. It also allowed his use of reports by other experts and the City’s own oversight agencies. The court concluded his opinions rested on a reliable foundation.

Relevance and Fit

The court also ruled on whether Lynch’s testimony would help the jury. The defense argued his report restated Swainson’s version of events. But the court found that Lynch’s summary aligned with the factual record. Lynch outlined how PPD failed to meet basic standards of supervision and discipline. He also addressed misconduct by Detective Santiago and its possible impact on Swainson’s case. The court noted that Lynch’s opinions did not cross into impermissible legal conclusions. Instead, they reflected professional standards in law enforcement. The court found his opinions would assist the jury.

Held

The Court denied the City’s motion to exclude the testimony of Michael K. Lynch.

Key Takeaway:

The court upheld Michael K. Lynch’s qualifications, methods, and relevance as a police practices expert. It ruled that his experience, review of misconduct patterns, and analysis of departmental failures provided reliable, admissible testimony that could assist the jury in evaluating Andrew Swainson’s § 1983 municipal liability claim.

Case Details:

Case Caption: Swainson v. City of Philadelphia

Docket Number: 2:22cv2163

Court Name: United States District Court for the Eastern District of Pennsylvania

Order Date: July 2, 2025

July 4, 2025
Expert Testimony on the Professional Standard of Law Enforcement Officers Excluded

Plaintiff Suzanne Stewart filed a gender discrimination and retaliation suit against the City of Arcola after Mayor Fred Burton terminated Stewart’s employment as “a direct result of policy violations related to insubordination and [her] unprofessionalism.”

Plaintiff filed a motion to strike the opinion of Defendant’s expert Michael W. Thaler.

Law Enforcement Expert Witness

Michael W. Thaler has extensive experience in law enforcement. He served as a law enforcement officer for over 40 years, during which he has served as the Assistant Chief of Police and Executive Assistant Chief of Police for the City of Houston and the Chief of Police for the City of Pasadena.

Want to know more about the challenges Michael W. Thaler has faced? Get the full details with our Challenge Study report.

Discussion by the Court

Defendant argued that Thaler offered an opinion on whether Plaintiff’s conduct could be considered insubordination. However, the Court held that Thaler’s declaration went well beyond that scope.

Thaler purported to analyze “the civil action filed on behalf of Suzanne Stewart regarding her allegations of being discriminated against and terminated when she complained of ‘inappropriate comments’ made by the Mayor which were directed at her.” However, that merely summarized the case. It was the responsibility of the Court to analyze the civil action, not that of a non-lawyer expert.

He further wrote that his “conclusions and opinions are based on an analysis of these materials by applying his law enforcement and administrative experience, education, and training regarding application of the applicable provisions of Texas and federal laws … Texas Administrative Code, Title 37; Texas Local Government Code 614; and Texas Occupational Code § 1701.452(a), (b).”

The Court found that these were attempts by a non-lawyer expert to present legal conclusions under the guise of a legal analysis on a case-dispositive issue.

At times, Thaler opines without rendering conclusions of law. For example, he writes that “there is no greater show of disrespect to the authority of a superior than to publicly challenge the decisions of a ranking officer with the type of profane laden language and unsupported salacious accusations as those made by the Plaintiff.” Nevertheless, the Fifth Circuit has recognized that expert testimony is unnecessary if “the jury could adeptly assess this situation using only their common experience and knowledge.”

The Court concluded that Thaler’s opinion was, at best, unnecessary and, at worst, untethered to his qualifications.

Held

The Court granted the Plaintiff’s motion to strike the opinion of Defendant’s expert Michael W. Thaler.

Key Takeaway:

Experts cannot render conclusions of law or provide opinions on legal issues. A jury, using their common experience and knowledge, could adeptly assess that publicly challenging a supervisor with profanity-ridden language while accusing them of extramarital affairs is indeed disrespectful.

Case Details:

Case Caption: Stewart V. City Of Arcola

Docket Number: 4:23cv4387

Court Name: United States District Court, Texas Southern

Order Date: June 24, 2025

June 28, 2025
Law Enforcement Expert Permitted to Testify on the General Reasonableness of Police Conduct

This lawsuit can be traced back to an incident that took place on November 11, 2019, in which Phoenix Police Department Officer Brittany Smith-Petersen shot and injured Plaintiff Krish Singh during a law-enforcement encounter.

Defendants brought a partial Daubert motion seeking to preclude certain portions of the intended testimony of Plaintiff’s use-of-force expert, Roger Clark.

Law Enforcement Expert Witness

Roger Clark is a retired law enforcement professional with 27 years of experience in the Los Angeles County Sheriff’s Department (LASD). He was hired on December 1, 1965, and served until his retirement on March 31, 1993. Throughout his distinguished career, he held several key positions, including six years as a Deputy Sheriff, six years as a Sergeant, and 15 years as a Lieutenant. Roger retired with a California Peace Officer Standards and Training (POST) Advanced Certificate and is a graduate of the POST Command College, class #5, 1988.

Get the full story on challenges to Roger Clark’s expert opinions and testimony with an in-depth Challenge Study.

Discussion by the Court

Ultimate-Issue Testimony

To begin with, Clark’s assertion that the Officers’ conduct was “in violation of . . . law as taught to all officers” does more than simply provide an aid to the jury’s deliberation. It was, on its face, a legal opinion. Although the statement is technically qualified by the phrase “as taught to all officers,” the Court found such qualification insufficient and more likely to confuse than to illuminate.

The rest of Clark’s report was more complex to evaluate. Many of the statements challenged by the Defendants use terms like “excessive” or “unreasonable.” These terms were tricky because they carried both everyday meanings and specific legal implications. It was appropriate for an expert like Clark to give opinions on what a reasonable police officer might do in a certain situation, based on standard training and professional norms. Using terms like “unreasonable” or “excessive” in that context does not automatically violate the Federal Rules of Evidence.

However, Clark was not allowed to directly state that Officers Smith-Petersen or Batway acted unreasonably. Such a statement crossed the line from expert opinion into a legal conclusion, which is not permitted. Clark’s report walked a fine line—sometimes staying within proper boundaries, and other times crossing them.

Most of the statements flagged by Defendants as improper could be corrected by rewording. Rather than examine every sentence now, the Court established a general rule and will address specific issues during the trial. Clark may testify about what constitutes reasonable or excessive force in general terms, but he may not say whether the specific officers in this case acted unreasonably or used excessive force.

Mental Health Diagnoses

Defendants argued that Clark’s report improperly offered an opinion about whether the Plaintiff was suffering from a mental disorder at the time of the incident. The Court disagreed, finding that this misrepresents the report. In the report, Clark explicitly stated that it is not the role or ability of police officers to diagnose a person’s disability. However, he also explained that officers are trained to recognize signs and cues that help them make appropriate decisions about how to respond. This training often involves mental health frameworks that guide officers in identifying possible mental health issues during their interactions with the public.

Based on this training, Clark opined that the Officers should have recognized that the Plaintiff might be mentally ill or emotionally distressed—especially when the Plaintiff repeatedly asked them to kill him, a clear indication of mental distress. Clark’s testimony is not a clinical diagnosis. Instead, it is an expert opinion about how a trained officer should interpret observable behavior in the field. The Court found this type of opinion to fall well within Clark’s area of expertise.

Defendants also took issue with a line in the report stating that the Plaintiff “suffered from PTSD, drug addiction, and ADHD.” But they failed to include the full context: that statement appears in the background section of the report and is explicitly attributed to the Plaintiff’s mother, Sunita Singh. Whether that statement qualifies as hearsay is not being decided here. What matters is that Clark himself did not diagnose the Plaintiff with any mental condition.

Contravention of the Video Evidence

Defendants’ final argument under Daubert is that Clark’s report relied on insufficient data because it allegedly contradicts the video footage of the incident. They claimed Clark misrepresented the facts by stating that the Plaintiff did not advance toward the officers, asserting instead that “the video clearly shows Singh advancing toward the officers multiple times.”

Defendants also argued that Clark’s report was flawed because he claimed the officers failed to use de-escalation techniques. In contrast, Defendants insisted that they did employ such techniques, including issuing over twenty commands for the Plaintiff to drop his weapon or stop moving, speaking with him, and reassuring him that they did not believe he was mentally unstable.

However, the Court found that most of Defendants’ arguments simply quoted portions of Clark’s report without explaining how those statements actually contradict the video evidence. Even in the few instances where Defendants attempted to point out specific inconsistencies, the Court found their arguments unconvincing.

Held

The Court granted in part and denied in part the Defendants’ partial Daubert motion to preclude certain portions of the intended testimony of Roger Clark.

Key Takeaway:

The Court ruled that while Clark may testify about general police practices and how a reasonable officer should interpret signs of mental distress, he may not offer legal conclusions—such as stating that the officers acted unlawfully or unreasonably. His mental health observations were deemed within his expertise and not clinical diagnoses. The Court also rejected Defendants’ argument that Clark’s report contradicted video evidence, finding their objections vague and unpersuasive.

Case Details:

Case Caption: Krish Singh V. City of Phoenix

Docket Number: 2:21cv99

Court Name: United States District Court, Arizona

Order Date: June 12, 2025

June 17, 2025
Law Enforcement Expert’s Opinion on Actual Events and Police Tactics Admitted
Plaintiff Gene Raymond Bell, Jr. claimed that Defendant Officers Anthonie Korkis, Arthur Bridgeforth, and Thomas Langewicz, II used excessive force while arresting him during a traffic stop on June 23, 2019 in Southfield, Michigan.

Plaintiff’s second motion in limine requested the Court to exclude or limit the testimony of Dr. Steven Amey, whom Defendants intended to call as an expert witness at trial.

Law Enforcement Expert Witness

Dr. Steven J. Amey is an associate professor of criminal justice at Ferris State University.

His research interests include computer forensics and new technology, use of force issues, police emergency driving and pursuit issues, firearms, ethics in criminal justice, criminal investigation techniques, patrol problems, interview and interrogation problem-based learning methods as well as body cameras.

Amey also holds a Ph.D. in Instructional Design and Technology from Wayne State University.

Get the full story on challenges to Steven Amey’s expert opinions and testimony with an in-depth Challenge Study.

Discussion by the Court

Plaintiff claimed that Amey’s opinion offered a legal conclusion that Defendants did not use excessive force. Plaintiff also claimed that Amey’s testimony will not be reliable because he assumed that Plaintiff initiated contact with Defendant Korkis through his car window, whereas the Sixth Circuit has already determined that the video footage is unclear about “who started it.” Finally, Plaintiff asserted that Amey’s testimony, which “frame[s]” Defendants’ side of the story as “factually established,” is more prejudicial than probative.

Analysis

Legal Conclusion

Plaintiff’s first contention is that Amey’s opinion offers a legal conclusion that the use of force was not excessive.

Unfortunately, Plaintiff did not explain the basis for believing Amey’s opinion offers a legal conclusion. Amey’s report discusses the laws Plaintiff was breaking when refusing to identify himself or provide documentation as requested; the specific training that officers receive to handle situations like the one involving Plaintiff; and the risks that Defendants would have faced had they permitted Plaintiff to come out of the car on his own. Therefore, the Court refused to exclude or limit Amey’s opinion.

Reliability

Plaintiff also contended that Amey’s opinion is not reliable because he assumed that Plaintiff is the one who initiated the first contact with Defendant Korkis—something that the Sixth Circuit stated is not clearly visible on the video footage. However, Amey did not make an assumption about first contact based on the video footage; rather, his expert report clearly states that he received this information from the police report. The Court will ensure that the jury is instructed that the factual dispute—whether Plaintiff or Defendant Korkis initiated the physical altercation—is in its hands.

Probative Value

Finally, Plaintiff contends that the introduction of Amey’s opinion will be more prejudicial than probative because his testimony will be “framed as if Korkis’ side of the story has been factually established[.]” If Amey frames his testimony as if Defendants’ position is factually established, Plaintiff has tools at his disposal to counteract the prejudice—namely, objecting to the misrepresentations contemporaneously and cross examining the witness to expose those flaws. On the other hand, the Court noted that Amey’s opinion has substantial probative value because it informs the jury about the training that officers receive for handling like situations, as well as the risks officers encounter when dealing with like situations, which goes to the reasonableness of force used under the circumstances.

Held

The Plaintiff’s motion in limine to exclude or limit the testimony of Dr. Steven Amey was denied without prejudice by the Court.

Key Takeaways:
- Amey’s opinion does not offer a legal conclusion about the use of force. Rather, his report discusses the laws Plaintiff was breaking when refusing to identify himself or provide documentation as requested.
- A use-of-force expert may express an opinion which is based on crediting, in a hypothetical sense, the testimony of one side of the dispute.
Case Details:

Case Caption: Bell V. Southfield Et Al

Docket Number: 2:19cv13565

Court Name: United States District Court, Michigan Eastern

Order Date: April 1, 2025
April 11, 2025
Law Enforcement Expert May Provide Testimony about the National and SLMPD Standards for the Use of Pepper Spray

Rev. Darryl Gray is suing the City of St. Louis and two St. Louis Metropolitan Police Department (SLMPD) detectives—Ronald Vaughan and Larry Wentzel—for violating his First and Fourth Amendment rights, as well as a variety of state law torts.

To support his constitutional claims, Rev. Gray hired Greg Meyer to give his expert opinion on some of the issues in the case.

Meyer’s expert report sets out his extensive experience in law enforcement, and Defendants do not challenge his qualifications. Instead, Defendants filed a motion to exclude five opinions in Meyer’s report as unreliable and not helpful to the jury.

Law Enforcement Expert Witness

Greg Meyer has 47 years of law enforcement experience, including 33 years as a police tactics and procedures consultant.

He has been an expert witness in numerous high-profile cases including Rodney King, Oscar Grant (the Oakland BART murder case), and George Floyd. He has been engaged in more than 400 civil and criminal cases as well as conducting outside independent reviews of use of force cases for a federal prosecutor and several district attorneys and police chiefs.

Discover more cases with Greg Meyer as an expert witness by ordering his comprehensive Expert Witness Profile report.

Discussion by the Court

Opinions 2 and 3 are excluded because the City was granted summary judgment

Opinions 2 and 3 in Meyer’s report relate to Rev. Gray’s Monell claims against the City of St. Louis.

After the motion to exclude was filed, the Court granted summary judgment to the City on Rev. Gray’s Monell claim. Opinions 2 and 3 in the report are therefore excluded because they will not “help the trier of fact to understand the evidence or to determine a fact in issue.”

Meyer’s Opinions

Meyer’s first opinion is:

“If the “Defendants’ actions violated Plaintiff’s First Amendment rights to freedom of speech and freedom of assembly by interfering with Plaintiff’s ability to associate freely in public and express Plaintiff’s views as part of a peaceful demonstration” as described in Para. 89 of the Second Amended Complaint, then the Defendants’ actions did not conform with proper contemporary law enforcement procedures.”

Meyer’s fourth opinion is:

“If Plaintiff did not push or otherwise assault or engage in preassault indicators against Defendant Vaughan’s allegedly pushing Plaintiff and using pepper spray on Plaintiff, and Officer Wentzel’s allegedly tackling Plaintiff to the street, did not conform with SLMPD policy or contemporary law enforcement training or procedures, and the resulting arrest and prosecution of the Plaintiff was false and malicious.”

Meyer’s fifth opinion is:

“If Plaintiff Gray did not assault Detective Vaughan, then both Detective Vaughan and Officer Wentzel appear to have violated SLMPD use of force policy and generally accepted police procedures when Detective Vaughan pepper sprayed Plaintiff Gray at extreme close range (inches); and Officer Wentzel used unnecessary and unreasonable force on Plaintiff Gray when he took him to the ground.”

Opinion 1 is Excluded Because it is not Helpful to a Jury

Defendants argued that his opinion will not be helpful to the jury because it is not based on “any specialized, scientific, or technical knowledge.” They claimed that the opinion says nothing more than “if the officers did it wrong, then they did it wrong.” The Court agrees with the Defendants.

Meyer’s opinion as formulated in his report tells the jury only that if Defendants’ conduct violated Rev. Gray’s First Amendment rights, then it did not conform with contemporary law enforcement procedures.

The Court ruled that Meyer’s first opinion does not provide any additional insight into police practices that might be helpful to the jury. His rationale for Opinion 1 makes that clear. The police procedures and practices he cites are a restatement of First Amendment law. Meyer does not even opine that he thinks Defendants’ conduct violated the First Amendment under the circumstances. He admits that the facts are disputed, and he cannot determine who is correct.

Opinions 4 and 5 are Excluded to the Extent that they State Legal Conclusions

In Opinion 4, Meyer’s analysis of law enforcement training is just a description of the Fourth Amendment and Supreme Court precedent. The Court determined that Meyer relied on the Constitution and Supreme Court precedent to form opinions on questions of law that will not “help the trier of fact to understand the evidence or to determine a fact in issue.”

In his rationale for Opinion 5, Meyer goes into more detail about SLMPD policy and accepted police procedure on the use of pepper spray but provides no analysis for his opinion that “Officer Wentzel used unnecessary and unreasonable force on Plaintiff Gray when he took him to the ground.”

Plaintiff argued that Meyer’s opinions are not legal conclusions because they provide “the jury with a framework for placing the jury’s own findings in the context of national police standards and SLMPD policies.”

In his rationale for Opinion 5, Meyer discussed the SLMPD’s and the International Association of Chiefs of Police’s (IACP) standards for pepper spray and opines that Detective Vaughan’s use of pepper spray did not comply with those standards. SLMPD and IACP standards are not common knowledge for jurors, and Meyer’s testimony will help contextualize the evidence the jury will hear about Detective Vaughan’s use of pepper spray.

Although Meyer’s report also states that Detective Wentzel’s “alleged tackling [of] Plaintiff to the street[] did not conform with SLMPD policy or contemporary law enforcement training or procedures,” the Court held that Meyer does not provide similar insight into accepted police procedure for that kind of force.

Held

The Court granted in part the Defendants’ motion to exclude Plaintiff’s expert, Greg Meyer.

Key Takeaway:

If Meyer had relied on SLMPD or IACP standards for uses of force like Wentzel’s, or explained why, based on his own extensive law enforcement experience, he believes Wentzel could have used less force to control Rev. Gray, the opinion might be admissible. But without that information, the Court cannot properly assess whether the opinion satisfies Rule 702‘s requirements.

Case Details:

Case Caption: Gray V. City Of Saint Louis, Missouri Et Al

Docket Number: 4:18cv1678

Court Name: United States District Court, Missouri Eastern

Order Date: March 31, 2025

April 4, 2025