Tear Gas Expert Witnesses: 9

Dennis Fivecoat has over 25 years of Use of Force and Firearm experience in the Military (20 years, retired) and private sector including significant training in the area of Civilian Law Enforcement.  He has attended numerous firearm and use of force related training courses including instructor development with local and federal law enforcement agencies, tactical firearm, close quarters battle, concealed carry, force-on-force training, use-of-force, and legal updates.

Litigation Support - As an instructor-trainer (Master Instructor) in firearms and less lethal devices (pepper spray, expandable baton, defensive tactics, handcuffing), Mr. Fivecoat has a practical and academic basis in the use of deadly and less-lethal use of force by civilians.  His experience teaching firearm use, defensive tactics, and use-of-force allow him to provide opinion on not only proper use of the tool or tactic utilized, but whether the actions were reasonable under the circumstances of the incident.

Mr. Fivecoat provides consultation and testimony on the reasonable use of force, self-defense, and defense of others. Private citizens may become involved in situations (shootings, brandishing, threats with weapons, excessive force, false arrest, false imprisonment) where the reasonableness and legality of their actions are challenged. Review of actions taken, firearm use, and the education of the expert provide the foundation for determining the reasonableness of each parties’ actions. Mr. Fivecoat will review the incident and opine based on local law, training standards, and the reasonableness of the use of force under the circumstances and conditions of the incident. 

Areas of Expertise:

Background - Dennis Fivecoat is a retired US Army physician assistant with a wide variety of functional background and experience. He has seen service in eight different countries encompassing desert, jungle, snow, and maritime missions. His past responsibilities range from combat in SW Asia to hospital duties as an ICU nurse in South Carolina. He has responded during national hurricane relief efforts and somewhat smaller Defense Support to Civil Authority (DSCA) missions. Click for Full Biography.

View Dennis Fivecoat's Consulting Profile.

Chief Chet Epperson (Ret.), MBA, has over 42 years of experience as a Law Enforcement / Police Professional for the Rockford Police Department in Rockford, Illinois. Chief Epperson spent 33 years as an active law enforcement officer and 10 of those years as Chief of Police. 

Chief Epperson maintains practical experience as a municipal police chief, implementing several police reforms in his police agency along with accountability processes. He was instrumental in reforming the Rockford Police Department by enhancing its relationship with the community and providing internal and external transparency. Chief Epperson assisted in the formulation of a multi-jurisdictional task force to investigate officer-involved police shootings, in-custody police deaths, and serious uses of force.

Litigation Support - Since 2016, Chief Epperson has been serving as a Police Practices consultant, providing court-appointed expertise in police agency Federal District Court Consent Decrees. He is an expert in applying Constitutional Standards, State Law, policy, and practice to police incidents. Having Instructed courses on police use of force, internal affairs, and discipline, Chief Epperson is qualified to opine on cases of this nature for both plaintiffs and defendants. His police and jail litigation services include thorough reporting, deposition, and trial testimony as needed.

Areas of Expertise:

View AGR Police Practice Group's Consulting Profile.

Dr. John R. Black is a recognized expert with extensive experience in international, federal, and state courts on Lethal Force, Police Use of Force, Officer-Involved Shootings, and Civilian Self-Defense, blending forensic analysis with human-centered perspectives and systems thinking. Dr. Black employs a systems thinking approach that enables him to view incidents from multiple perspectives. He regularly speaks to Police leadership, investigators, lawyers, and organizations about how we think about the process of inquiry, our biases, and our sensemaking.

Litigation Support - Dr. Black is qualified as an expert witness in state and federal courts related to police practices, police use of force, decision-making, officer-involved shootings, police tactics, police training, incident command, and police / jail operations. He is also qualified with similar expertise for civilian self-defense and use of force events.

Expert in Use of Force & Lethal Force Incidents & Decision-Making

In cases involving force--lethal force, understanding decision-making is as critical as the facts themselves. Whether you are a defense attorney explaining your client’s actions or a prosecutor challenging them, you need an expert who integrates both events and decision-making processes. Dr. Black offers a unique approach, blending quantitative precision with qualitative insight into how individuals make sense of their world. he is a recognized expert with experience in international, federal, and state courts on lethal force, police use of force, officer-involved shootings, and civilian self-defense. He combines forensic analysis with human-centered perspectives, ensuring a balanced view that benefits both defense and prosecution.

Advanced Forensic Video and Qualitative Analysis

Video evidence often plays a pivotal role in determining the facts. Dr. Black is skilled in forensic video analysis, using Amped Five software to extract key details. What sets him apart is his ability to combine video analysis with qualitative thematic tools like Atlas.TI, understanding both what happened and how individuals interpreted their environment under stress.

Cognitive Interviewing and Human Performance Expertise

Dr. Black specializes in cognitive interviewing, exploring clients’ mindsets during critical moments leading up to the use of force. His approach bridges the quantitative analysis of human performance with qualitative insights into violent encounters, offering a comprehensive view of why actions were taken.

Military and Law Enforcement Expertise

With 30+ years in U.S. Army Special Forces and 23+ years in law enforcement, Dr. Black brings unmatched experience to each case. He provides practical insights grounded in real-world experience. His background ensures a comprehensive understanding of how policy, training, and decision-making intersect under pressure.

View Aragon National, Inc.'s Consulting Profile.

My name is David T. Sweeney.  I am a Police Policy and Procedure expert and a retired 34-year veteran police leader with Seattle Police and Oregon State University PD.  I have decades of experience supervising a large number of police officers and supervisors. I am currently employed as adjunct faculty in the School of Police Staff and Command at Northwestern University. I enjoy assisting with expert reviews of policing best practices for a variety of legal standards for police departments. As an expert witness, I have been pleased to work with both plaintiff and defense attorneys. I will give you an honest assessment of your case, so that I can provide the best reports and helpful testimony. I have experience with 41 total cases: 16 defense cases and 25 plaintiff cases.

Litigation Support - My goal is to improve best practices in policing by offering expert witness and police consultation services. I am also a trained mediator specializing in workplace conflicts. I provide honest, unbiased opinions. I will be happy to review and discuss your case. I will point out strengths and weaknesses of the case, and we can work on next steps, whether it be further case review, expert report, deposition, or trial testimony. I have spent 21 years as a sergeant and lieutenant, responsible for training and reviewing topics such as police pursuits, use of force, police tactics, de-escalation, police supervision, less lethal weapons, active shooter, SWAT, crowd control, legal standards, EEO, Human Resources, U.S. 1983 cases, and more.

 Areas of Expertise:

View David T. Sweeney's Consulting Profile.

Joseph E. Gunja is a Jails, Prisons and Corrections Expert with more than 30 years of experience in the corrections industry. Mr. Gunja had a distinguished career with the Federal Bureau of Prisons (FBOP) for over 28 years serving as a Correctional Officer, Shift Supervisor, Investigator, Captain, Associate Warden, and Warden at three complex correctional facilities. 

He also served as Regional Director of the Western Region for over 2 years and was assigned to the FBOP's Headquarters in Washington, DC where he was responsible for authoring national policy and official publications, providing technical expertise to the Assistant Director of Correctional Programs and facility Wardens, Associate Wardens, and Captains. 

After retiring from the FBOP in 2007, Mr. Gunja has been providing correctional consultation and expert witness services. In addition, he has worked for two of the largest private corrections companies, CCA and GEO Group, as Warden at the Northeast Correctional Center in Youngstown, Ohio, and the Great Plains Correctional Facility in Hinton, Oklahoma. 

Litigation Support - Joseph Gunja has an over 90% success rate in all cases he has been retained as an expert, both working with plaintiffs and defendants, as well as several cases of sentencing mitigation or reductions.  While some cases were settled in lieu of court, the settlements were all in favor of the attorneys or firms he represented. He offers advice, expertise, and expert testimony for a variety of issues in matters pertaining to: 

View Simco Correctional Consulting's Business Consulting Profile.

Dr. Roy G. Taylor is a current Chief of Police with over 40 years of experience in a wide-range of federal, state, local, and private criminal justice positions. Dr. Taylor specializes as an expert witness in Police Practices and Procedures and Law Enforcement and Criminal Justice. Current Positions:

• Chief of Police Blue Ridge Public Safety (2014)
• President/CEO Signal 88 Security of Charlotte (2012)
• President/CEO Capitol Special Patrol (2012)
• Chief of Police Capitol Special Police (2002)
• Lt. Colonel – Provost Marshal, Army National Guard (2000)
• Antiterrorism / Emergency Management Branch Chief DoD (2007)
• Provost Marshal Joint Civil Support Task Force, Joint Chiefs of Staff (2014)

Litigation Support - Dr. Taylor is called upon to analyze cases from both defense and plaintiff perspectives. His services include case review, written reports, deposition, and trial testimony as needed. 

Areas of Expertise:

View Roy Taylor's Consulting Profile.

“We settled the case...for $5 million. Your report played a huge role in that.  Thank you for everything!”  Nicolas H. 

Beth A. Mohr, CFE, FSA, CFCS, CAMS, CCCI, MPA, PI, is a Police Practices expert with over 30 years of sworn and non-sworn investigative experience.  Ms. Mohr has testified as an expert in numerous state and federal court proceedings, depositions, and administrative hearings federal and state courts, including New Mexico, Ohio, Illinois, Arizona, California, and Washington state.  Ms. Mohr has testified on a variety of subjects, including police procedures, police misconduct, white collar crime and fraud examinations.  Her expertise has been verified by the courts via a Daubert challenge, in which Ms. Mohr was found to be qualified as an expert in police practices generally, and well as the specific areas of interviewing, interrogation, false and recanted confessions, cognitive bias, investigations and investigative failures, vice, and human trafficking.  Ms. Mohr is neutral, fair, and her opinions are rooted in provable facts, as well as academic literature, where appropriate.  She strives to balance her cases between defense and plaintiff-sided cases, and also provides habeas consulting services.  

Ms. Mohr is credentialed as a Nationally Certified Law Enforcement Instructor by the IADLEST, and is one of fewer than 150 individuals who have been nationally certified as an expert law enforcement instructor.  She is a Certified Fraud Examiner, Certified Force Science Analyst (FSA) Certified Anti-Money Laundering Specialist (CAMS), Certified Financial Crimes Specialist (CFCS) and a Certified Cyber Crimes Investigator (CCCI).  She is also a Private Investigator (PI) licensed in New Mexico, Arizona, Texas, and California.  

Areas of Expertise:

• Police Practices and allegation of Police Misconduct
• Excessive Force, Deadly Force & Use-of-Force
• Taser, ECWs, and other uses of force intended to be less-lethal
• Interviewing, Interrogations & False and Recanted Confessions
• Police Ethics
• Investigative Failure, Cognitive Bias, Confirmation Bias
• Habeas Consulting, including death penalty cases
• False Arrest
• Failure to Train / Failure to Supervise               
• Evidence Handling
• Police Policy, SOPs
• Fraud & White-Collar Crime
• Vice & Human Trafficking
• Money-Laundering Cases
• Cryptocurrencies / Bitcoin
• Retaliation & Qui Tam
• Workplace Violence & Sexual Harassment
• Private Investigations & PI Failures

During her career with the San Diego Police Department, Ms. Mohr was awarded three Commanding Officer’s Citations, which were the highest awards offered by the San Diego Police Department for investigative acumen at the time.  After retiring from the San Diego Police Department, she conducted death penalty mitigation investigations, and other complex felony investigations, including homicide and white-collar cases, for the Whatcom County, Washington, Public Defender’s Office.  This includes conducting investigations of allegations of police misconduct for the City of Albuquerque Independent Review Office. Ms. Mohr recently chaired the City of Albuquerque’s Police Oversight Board, a civilian board which was created as part of the US Department of Justice’s Consent Decree with the City of Albuquerque and the Albuquerque Police Department.

Ms. Mohr has published a chapter entitled “Skepticism”, in the newly-released book The Art of Investigation Revisited, as well as having penned articles for bar journals and other peer-reviewed publications.  Ms. Mohr has taught courses on law enforcement topics including interviewing techniques, investigative ethics, evidence collection, financial and fraud investigations, and many other topics.  Her ethics courses, investigative courses, and fraud courses are certified for law enforcement credit.  

Emanuel Kapelsohn is an internationally recognized Firearms Training and Use of Force consultant who has instructed thousands of police and security officers, federal agents and others throughout the U.S. and abroad since 1980. A graduate of Yale University and Harvard Law School, he is a practicing attorney in addition to his consulting work. 

As vice president of the Internat’l Assoc. of Law Enforcement Firearms Instructors, Mr. Kapelsohn is a certified in force science and shooting scene reconstruction, and as an instructor in numerous law enforcement disciplines. He is a featured presenter at national and international instructor conferences. He has authored over 130 published articles, is Associate Editor of "Standards & Practices Guide for Law Enforcement Firearms Instructors," and principal author of "Firearms Training Standards for Law Enforcement Personnel," and "Guidelines for Simulation Training Safety." 

Mr. Kapelsohn testifies as an expert witness in civil and criminal cases in state and federal courts nationwide, and has testified by invitation before both houses of Congress. 

Testimony on the Following Subjects:

View Emanuel Kapelsohn's Consulting Profile.

Adam Bercovici has over 40 years of experience in the Police and Security field. Mr. Bercovici spent 30 of those years with the LAPD, 20 as a supervisor and manager. He is currently a retired LAPD lieutenant and former security company CEO.

Background: Mr. Bercovici's leadership assignments included the Criminal Investigation Section- Major Crimes Division-The Joint Terrorism Task Force, The FBI Violent Crime Task Force ( where he supervised the FBI Fugitive Task Force), The Special Investigation Section, and Homicide Special Section. 

Since 2012, Mr. Bercovici has worked as a licensed private investigator and subject matter expert, and consultant in the areas of Police Practices and Complex Police Investigations. His clients have included major law firms, insurance companies, and corporations.  Mr. Bercovici is currently retained on several high-profile cases.  He is an experienced Expert Witness who has written numerous Rule 26 Reports and has testified in both State and Federal courts.  Writing examples can be provided.  Mr. Bercovici has been an on-air talent, producer, and script and story consultant in the entertainment industry.  He was the Co-Talent on The History Channel Series JFK Declassified-Tracking Oswald.  Mr. Bercovici was the Executive Producer for American Cartel for Discovery Plus. 

Litigation Support: Adam Bercovici splits his work between defense and plaintiff. He has been retained by major civil rights firms, major municipalities and their legal counsel, plaintiff attorneys, city attorneys, and criminal defense attorneys. Mr. Bercovici accepts work based on the merits of the individual case.

Areas of Expertise: