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.

Tony Turnbull is a retired Sergeant with the Sacramento County Sheriff's Office. He has over 30 years of Law Enforcement experience with over 20 of those years in Criminal Investigations.  Sgt. Turnbull spent over 20 years of his career in Investigations, including 6 years in Gangs and Narcotics and 16 years in the Homicide Bureau, including 3 years as the Homicide Bureau Supervisor and 5 years in Cold Case Investigations. 

Sgt. Turnbull is currently providing consulting and expert witness services, instructor with Robert Presley's Institute of Criminal Investigations, and working cold case homicide investigations as a retired annuitant at the Sacramento County Sheriff's Office.

Litigation Support - Sgt. Turnbull provides expert witness testimony and consulting services in both civil and criminal litigation, offering clear, methodical, objective opinions grounded in law enforcement standards, policy compliance, and constitutional policing. He also provides expert review of historical police investigations, applying current or past professional standards to cases. Domestic and international travel offered as needed.

Areas of Expertise:

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 subject matter expert and consultant in 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 prominent 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: 

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.

“We settled the case...for $5 million. Your report played a huge role in that.  Thank you for everything!”  Nick 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 in 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 & Ethical Failures
• Cognitive Bias, Confirmation Bias
• Investigative Failures
• False Arrest
• Failure to Train, Failure to Supervise, Monell Claims
• Evidence Handling
• Police Policy, SOPs
• Habeas Consulting, including death penalty cases
• Vice & Human Trafficking
• Sexual Assault
• Fraud & White-Collar Cases
• 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 that 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.

Dr. Theron L. Bowman is a nationally recognized expert in Police Practices, Constitutional Policing, and Law Enforcement Oversight with more than 40 years of experience in public safety leadership, consulting, and litigation support. A former Chief of Police and Deputy City Manager for Arlington, Texas, he is the founder and CEO of The Bowman Group, a consulting firm specializing in police reform, accountability, and compliance monitoring.

Dr. Bowman has served as an expert in state and federal cases involving use of force, civil rights, internal investigations, and policy failures. His work spans major U.S. jurisdictions including New York City, Baltimore, Chicago, Memphis, Phoenix, Seattle, and Los Angeles County, and he has advised international policing initiatives in Bosnia, Kosovo, Haiti, Israel, Jordan, Iraq, and Afghanistan.

Litigation Support - Dr. Bowman has served as an expert in state and federal cases involving use of force, civil rights, internal investigations, and policy failures. His work spans major U.S. jurisdictions including New York City, Baltimore, Chicago, Memphis, Phoenix, Seattle, and Los Angeles County, and he has advised international policing initiatives in Bosnia, Kosovo, Haiti, Israel, Jordan, Iraq, and Afghanistan.

Attorneys and agencies retain Dr. Bowman for his deep operational insight, courtroom-tested credibility, and ability to translate complex police practices into clear, objective analysis.

Areas of Expertise:

Background Experience - Dr. Bowman holds a Ph.D. and MPA from the University of Texas at Arlington and is a graduate of the FBI National Executive Institute, FBI National Academy, and Senior Management Institute for Police.

A former CALEA Commissioner, Dr. Bowman has trained and advised agencies on constitutional policing, leadership, and accountability. His key areas of expertise include use of force, civil rights, police supervision, misconduct investigations, bias-free policing, and major event security.

He has held leadership roles with the International Association of Chiefs of Police and coordinated security for events such as the Super Bowl and World Series. His reform work includes guiding agencies under DOJ consent decrees and developing policies that strengthen accountability and community trust.

theron.bowman@tbowmangroup.com | (817) 502-9197

View The Bowman Group'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.

Dr. James F. Pastor, Ph.D, JD, CPP, is a multifaceted security expert with a rich background that spans security, policing, legal, 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, policing, and public safety.
 
 Transitioning from the streets to the courtroom, Dr. Pastor built a distinguished legal career representing police unions, security guard and electronic security firms, corporations, and religious institutions. His comprehensive counsel and advice to litigation attorneys, corporate counsel, and policy makers is grounded on real world experience and practical understanding.
 
With a doctorate in Public Policy Analysis, Dr. Pastor brings vision and understanding of how policies shape incentives and influence human behavior. This academic insight, combined with his extensive 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 impact.
 
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 in a variety of settings.

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 750 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.

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.

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:

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.

Daniel G. O'Kelly has over 46 years of experience as a range instructor, firearm designer, builder, auditor of licensees, collector, and expert on firearms and ammunition. 

Mr. O'Kelly served for 11 years as a Police Officer and for 23 years as a Special Agent for the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). As one of ATF’s leading firearm experts, he was Lead Instructor of Firearm Technology at the ATF National Academy. Since his retirement from the ATF, he has served as a Senior Corporate Manager for Cabela’s, the then largest firearm retailer in the world, where he co-developed a firearm technology and ATF compliance training program for that company, and is the Founder/Director of IFSA. 

Mr. O'Kelly then founded and is the Director of, the International Firearm Specialist Academy (IFSA), a guild of award-winning experts, former Federal Agents, Investigators, Police Officers, Medical Doctors, and an Attorney, in the Firearm and Forensics field.

Litigations Support -  Mr. O'Kelly has testified continually in depositions and in criminal & civil cases in State, Superior, Circuit, District and Federal Courts since 1978, and has been recognized as an expert witness in Federal and State courts since 1990. He has opined on the topics of:

 Noteworthy Cases

• Retained as Defense expert in the Alec Baldwin case.
• Testified in four Federal trials on the topic of federal firearm definitions from 2014 to 2019 which resulted in ATF undertaking a 2-5 year rewrite of the definition of a firearm “frame or receiver”, which reached a SCOTUS decision in 2022. 
• Testified in trials wherein 1289 items of firearm-related evidence were ruled out by the Court as a direct result of his testimony.
• Worked undercover in three international illicit arms dealing cases, including the Diveroli case which sparked the movie "War Dogs", and is one of two ATF Agents to ever perform an undercover investigation of illicit international firearm trafficking in Europe.   

View Daniel O'Kelly'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.

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

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.