Police - Law Enforcement Expert Witnesses: 19

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. 

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: 

What Really Happens Inside a Prison

Mr. Gunja 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.

View Simco Correctional Consulting's Business Consulting Profile.

Aaron T. Olson specializes as an expert in police investigations and employer investigations. His knowledge and skills come from a career in law enforcement, testifying in state and federal court, being an expert witness, private investigator, adjunct professor, author and trainer. 

Background Experience: Mr. Olson has 26 years of police experience with the Oregon State Police managing assignments in communications, recruitment, and patrol. He supervised and evaluated both police and non-police employees. He was a member of the OSP Procedures and Rules Advisory Committee and worked with Oregon's Department of Justice legal team in rewriting and validating OSP's trooper and cadet applicant hiring process. 

As a patrol supervisor, Mr. Olson directed major crime scenes and motor vehicle fatalities investigations. He reviewed and approved administrative, police, and use of force reports. He investigated allegations of police officer misconduct, conducted background checks, and participated in specialized tasks in community policing, dignitary protection with the U.S. Secret Service and other law enforcement agencies. In his tenure he had experience in police pursuits, the use of physical force and deadly force and next-of-kin death notifications.  

Mr. Olson is a former human resources investigator with Local Government Personnel Institute, Salem, OR. He conducted background and misconduct investigations on city and county employees and city and county elected officials, as well as city police chiefs. His misconduct investigations included sexual harassment, discrimination, retaliation and hostile work environments. He wrote the investigative reports and made the findings of facts on all misconduct allegations.

Besides being an expert witness, Mr. Olson is a private investigator. He is insured and bonded and licensed through the Oregon Department of Public Safety Standards and Training, Private Investigator License #113509. Mr. Olson is a contract expert consultant to the Oregon Public Defense Commission on police practices and investigations. His vendor number is 1833121097-000. 

Mr. Olson is a published co -writer of multiple books, CARE Approach: Seeking Solutions to Human Problems and Multicultural Law Enforcement: Strategies for Peacekeeping in a Diverse Society. Further, he is an adjunct professor teaching at a community college and state university.

Litigation Support: Mr. Olson meets the criteria of an expert witness as outlined in the Federal Rules of Evidence. He has experience as an expert on cases involving police misconduct, police procedures, police and non-police use of force, police pursuits; wrongful death; personal injury; employer investigations on employees; and cases involving employer negligent hiring, negligent training, negligent supervision, negligent retention, management performance and retaliation. He also has experience in reviewing criminal cases for defense attorneys. Mr. Olson's services are available to attorneys' representing plaintiffs and defendants and include diagnostics, thorough reporting, depositions, arbitration hearings, and trial testimony as needed. Contact him today for a free initial consultation.

Areas of Expertise:

View Aaron T. Olson's Consulting Profile.

Chief Chet Epperson (Ret.), MBA, has over 44 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.

Cameron Consulting is a physical skills teaching firm that provided contractual instruction to Police Agencies; College Districts; Private Security Companies; Private Corporations and the United States Military for 52 years, having trained approximately 40,000 Enforcement Officers on Arrest Control Tactics and Weaponless Defense.   

Don S. Cameron is a former Staff Member at Santa Rosa Criminal Justice Training Center, Napa Valley College Police Academy, San Joaquin Delta College Police Academy, San Francisco Police Academy and Contra Costa County Sheriff’s Law Enforcement Training Center.  He was a police Officer and Supervisor for 16 years with the Berkeley Police Department and the San Francisco Bay Area Rapid Transit Police Department. 

Worked as a police physical skills and classroom instructor for 52 years. A member of P.O.S.T.’s subject matter expert committee on use of force and less lethal control devises.  Member writer of Learning Domain #20 (use of force), #24 (crowd control), #33 (arrest methods/defensive tactics), #35 (firearms) & #37 (people with disabilities) for the P.O.S.T. Basic Academy.

Litigation Support - Mr. Cameron has served as an Expert Witness on Police Practices cases and Law Enforcement Training for the past 46 years, testifying approximately 500 times. His services include case review, thorough reporting, depositions, and testimony as needed.

Areas of Expertise:

Donald L. Leach, II, is a Jail / Corrections Management expert with over 30 years of experience. He has 20 years of consulting experience on jail management issues nationally, focusing on Risk Management for Jails and Jail Operational Methodology. 

Mr. Leach has extensive supervisory experience, having overseen up to 402 employees (indirectly). He also supervised internal affairs investigations, experienced in interviewing, hiring, training, scheduling, motivating, evaluating, and dismissing personnel. He is experienced in administering and managing a large detention facility, developing and administering programs, budgeting, contract development and monitoring, conducting research, monitoring compliance with policies and procedures, community relations, public speaking, controlling costs, problem-solving, and preparing reports.

Litigation Support - Mr. Leach has served as an expert witness for 5 years, in both State and Federal court. His services are available to counsel for both Plaintiff and Defense and include case review, testimony, and consultation for jail and prison issues.

Areas of Expertise:

View Donald Leach's Consulting Profile.

Dr. Ron Martinelli, PhD, CMI-V, is a nationally renowned Forensic Criminologist and a federal/state courts qualified law enforcement and premises liability expert who is also a Certified Medical Investigator (physician's level) and a Certified Suicide Investigator. 

Dr. Martinelli directs the nation's only Forensic Death Investigations & Independent Review Team of 26 law enforcement, forensic and medical experts and specializes in officer-involved death cases, civilian self-defense shooting cases and premises liability/security cases. He is a forensic/law enforcement expert to the U.S. Department of Justice, several State Attorney Generals' Offices, numerous major municipalities and nationally prominent private law firms specializing in wrongful death, civil rights and premises liability. 

Dr. Martinelli is the prevailing expert in over 90% of his retained cases. He has saved defendants over $650M and earned plaintiffs over $290 million in jury verdicts and settlements since 2004. He is the media's go-to forensic expert for FOX News, One America News Network, CNN, HLN, Sky News, BBC, NPR, and the History & Discovery Channels. Dr. Martinelli is skilled in officer-involved shootings, in-custody deaths, crime scene reconstruction, forensics, applied sciences, human factors, psycho-medical emergencies and premises liability and security cases. His unique and extensive field experience, combined his academic and scientific credentials, excellent written reports and persuasive testimony, make him a very appealing expert to attorneys and juries alike.

Areas of Expertise:

• Arrests
• Search & Seizure
• Use of Force / Excessive Force - All Levels and Weaponry
• Officer Involved Shootings(OIS)
• In-Custody Deaths
• Criminal Investigations
• Law Enforcement & Corrections Practices, Training & Supervision
• Adult & Juvenile Corrections
• Law Enforcement Negligence
• Civilian Self-Defense, Premises Liability, Security, Foreseeable Harm
• Insurance Cases
• Human Factors

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.

Daniel G. O'Kelly has over 40 years of experience as a range instructor, a builder, and collector ofFirearms and Ammunition. Mr. O'Kelly is currently Director at the International Firearm Specialist Academy (IFSA), a guild of award winning experts, former Federal Agents, Investigators, Police Officers, Attorneys, and Medical Doctors, in the firearm and forensics field.

Background Experience - An Armorer for fourteen firearm manufacturers, Mr. O'Kelly has toured and done research at numerous firearm and ammunition factories and firearm reference collections across the U.S., Europe, and Africa. He also served for years as a Compliance Manager for the world’s largest firearm retailer. He regularly presents seminars on firearm enforcement, ID & technology, and ammunition to law enforcement and the firearm industry. He has been a court-qualified expert witness since 1990 on firearms, ammunition, self-defense, use of force, ballistics, trade dress, etc… Mr. O'Kelly served for 11 years as a Police Officer and for 23 years as a Special Agent for the Bureau of ATF where he was Lead Instructor of Firearm Technology at the ATF National Academy, where he co-wrote the firearm lesson plans.

Litigation Support - Daniel O'Kelly has provided litigation support as an Expert Firearm Witness in federal court since 1990. He has testified in numerous trials for over 35 years and has been lauded as an "unshakable witness". A qualified Subject Matter Expert with exceptional knowledge in firearms and investigative protocol, he is recognized as a “go to” person regarding technical firearm issues.

Areas of Expertise:

View Daniel O'Kelly's Consulting Profile.

USE OF FORCE & POLICE PRACTICES EXPERT

Brian L. Landers is considered one of the top police practices experts in the United States based on his diverse experience and impeccable report writing and testimony skills. Brian has nineteen years in Law Enforcement as well as over 25 years in law enforcement training and education, including experience as a police and jail academy director and a full-time criminal justice professor. He has served as an expert for both the plaintiff and defense in over seventy cases involving law enforcement and corrections in federal courts across the United States.

Experience: A former law enforcement officer, Brian started his career in patrol and K-9 and was promoted to supervision as a sergeant and eventually as a lieutenant in charge of the agency's training, tactical unit, and hiring procedures. He also handled a variety of investigations and use of force reviews for various agencies.

Brian currently works full-time as a professor of Criminal Justice. He was appointed by the Wisconsin Department of Justice to serve on the state's Tactical Advisory Committee and Law Enforcement Ethics Advisory Committee, was a Wisconsin Criminal Justice Coordinators Committee President, and was appointed by the Wisconsin State Legislature to the state 911 Advisory Committee. He also was elected to three terms as Mayor of the City of Wisconsin Dells and three terms on the County Board of Supervisors (Columbia Co. WI).

Brian frequently serves as a media consultant on police and criminal justice issues for ABC, NBC, CBS, and Fox News affiliates, and has authored columns for Officer Magazine on police practices, training, and use of force.

Areas of Expertise:

Education:

View Brian L. Landers' Consulting Profile.

David W. O`Laughlin is an experienced, innovative leader in the world of Law Enforcement Training. Having been directly involved in the training of police officers for more than 35 years, he has obtained certifications in a multitude of disciplines and has become a Master Use of Force Instructor and Force Science Analyst.

Mr. O'Laughlin recently retired from the Brookline Police Department. As President of the Massachusetts Police Training Officers Association, he was appointed by Governor Weld to serve on the Executive Board of the Massachusetts Criminal Justice Training Council and later appointed to the Committee for Law Enforcement Training and Education by Governor Romney.

Mr. O'Laughlin is a certified expert in the Use of Force and is a recognized consultant in that discipline.

Litigation Support: David W. O'Laughlin provides expert incident analysis and testifies in both court and deposition in matters of police use of force, up to and including deadly force. His services are available to police agencies, insurance companies, and attorneys representing both plaintiff and defendant.

Areas of Expertise:

View David O'Laughlin's Consulting Profile.

Victor Lofgreen, PhD has over 30 years of experience and education in the fields of Corrections and Community Development. He is a prison and jail consultant who conducts cases analysis and develops reports to support litigation on prison and jail issues. Experience - Dr. Lofgreen has served as the CEO of a State Adult Correctional Institution and the Division Chief of a State Planning Agency for Corrections. He has authored numerous professional papers and articles on topics within his area of expertise as well as Agency Policy and Procedure Manuals and training materials. Litigation Support - Dr. Lofgreen's expertise is in Jail and Prison Policy and Procedures related to the standard of care for inmates by local, State, and Federal correctional agencies. His services are available to counsel representing plaintiff and defendant and include case review, case study and data analysis, report of Expert Opinion based on the evidence included in the case study, deposition, and trial testimony as needed. Areas of Expertise:

Timothy A. Dimoff, CPP, founder and president of SACS Consulting & Investigative Services, Inc. a leading security consulting firm, has over 40 years of experience in Law Enforcement and Security matters for both the public and private sectors. He is multi-certified in the security field and is considered one of the nation's leading authorities on negligent security procedures; security & vulnerability issues; police procedures and operations including use of force; high-risk workplace and human resource issues; narcotics investigations and enforcement. 

Mr. Dimoff is board certified by ASIS as a Certified Protection Professional (CPP?) which is internationally recognized as the “gold standard” certification for security management professionals, demonstrating their knowledge and competency in seven key domains of security.

Litigation Support - Mr. Dimoff has over 20 years of experience in testifying and consulting as an expert witness in over 500 cases and trials for both the plaintiff and the defense sides. His expert witness experience includes law enforcement procedures, security negligence of business or physical premises, human resources issues, meeting standards of practice in hiring and termination, employment practices, proper documentation, training, supervision, policies and procedures, harassment, discrimination, internal investigations, threats and excessive use of force.

Mr. Dimoff is a renowned speaker, trainer, and author who has offered expert commentary to national media including Dateline, NBC, CNN, The Chicago Tribune, The New York Times, The LA Times, The Washington Post, and The Wall Street Journal.  He is the author of four books, including How to Recognize Substance Abuse, The YOU in Business, and Life Rage, a chilling examination of societal rage and safeguards against it.

Mr. Dimoff holds a Bachelor of Science Degree in Sociology with an emphasis in Criminology from Denison University.

Areas of Expertise: 

View Timoth A. Dimoff's Consulting Profile.

Dr. James F. Pastor, Ph.D, JD, CPP, is a multifaceted security expert with a rich background that spans security, policing, legal, public policy, and academia. His career began as a tactical officer in Gang Crime Enforcement with the Chicago Police Department, where he gained hands-on experience in one of the nation's most dynamic policing environments. This real-world foundation laid the groundwork for his extensive expertise in security and public safety.

Transitioning from the streets to the courtroom, Dr. Pastor built a distinguished legal career representing police unions, security guard firms, and electronic security companies. His legal acumen allows him to provide comprehensive counsel and advice on various security and public safety matters.

With a doctorate in Public Policy Analysis, Dr. Pastor has a nuanced understanding of how policies shape incentives and influence human behavior. This academic insight, combined with his practical experience, gives him a unique perspective on risk and liability, making him a sought-after advisor for corporations and communities aiming to prevent crime or mitigate its impacts.

Dr. Pastor's "security sense" is a blend of street-level policing intuition, academic scholarship, legal expertise, and technical know-how, further enhanced by a deep understanding of geopolitical trends. His decades-long study of terrorism and extremism also informs his work, allowing him to contribute valuable insights and assessments for your case.

Areas of Expertise:

Litigation Support - Dr. Pastor is a highly regarded expert witness with experience in policing, security, public safety, and legal issues relating to these. His depth and breathe of experience is substantive, yet practical. Bringing a unique background, along with credentials and skills, including participating in over 700 prior depositions, has proven to be very effective in his expert witness role.

Dr. Pastor has over 20 years of university teaching experience in security, public safety, and policing, including Northwestern University- Center for Public Safety and the International Law Enforcement Academy. 

Author of four books on security and public safety, plus chapter on Private Policing in ASIS International's Protection of Assets Manual and created Privatization of Policing Bibliography for Oxford University Press, both being comprehensive, substantive works relating to Private Policing.

View SecureLaw LLC's 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.