Police - Law Enforcement Expert Witnesses: 21

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 65+ total cases: 1/3 defense cases and 2/3 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.

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.

Andreu Experts is a premier expert witness and consulting firm specializing in Law Enforcement Practices, with a distinct focus on Homicide Investigations, Use of Force, and Complex Criminal Case Analysis. Founded by a former Chief of Police with more than 45 years of distinguished law enforcement experience—including over two decades dedicated to homicide investigations—Andreu Experts delivers authoritative, fact-driven opinions grounded in real-world investigative leadership.

Their firm provides comprehensive expert services to both plaintiff and defense attorneys in state and federal courts. They are retained in cases involving wrongful death, police procedures, investigative failures, officer-involved shootings, and allegations of misconduct. Every opinion rendered is the product of meticulous case review, careful analysis of reports, witness statements, forensic evidence, and adherence to generally accepted law enforcement standards and practices.

What distinguishes Andreu Experts is not only the depth of experience, but the credibility and clarity brought to each case. Having led major investigations and supervised detectives in high-stakes environments, their principal understands how investigations should be conducted—and where they fall short. This perspective allows them to identify critical issues, explain complex procedures in plain terms, and assist attorneys in building compelling, well-supported arguments.

Services include case evaluation, report writing, deposition and trial testimony, and trial preparation support. They work closely with legal teams to strengthen case strategy, anticipate opposing arguments, and present findings in a manner that resonates with judges and juries alike. Whether retained early in litigation or brought in to assess an existing case, Andreu Experts provides objective, defensible opinions that stand up under scrutiny.

Andreu Experts' commitment is to professionalism, integrity, and precision. They do not advocate—they analyze. Their role is to assist the trier of fact in understanding what occurred, why it matters, and how it aligns with accepted law enforcement standards. When experience matters and credibility is critical, Andreu Experts is a trusted partner in the pursuit of justice.

Aaron T. Olson specializes as an expert in police practices and human resources lawsuits. His knowledge and skills come from a career in law enforcement, former human resources investigator, 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 with management 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 personal 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. The 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 defendant use of force. His vendor number is 1833121097-000. 

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.

Expert Witness: Mr. Olson has experience as an expert on cases involving police misconduct, police procedures, police use of force, police pursuits, wrongful death, personal injury, citizen use of force, murder, manslaughter, attempted murder, assault, felon in possession of a firearm, employer investigations on employees, employer negligent hiring, negligent training, negligent supervision, negligent retention, management performance and retaliation. He has experience in testifying in civil and criminal court cases, as well as civil depositions. Mr. Olson's services are available to attorneys' representing plaintiffs and defendants in state and federal court cases. Contact him today for a free initial consultation.

Areas of Expertise:

View Aaron T. Olson's Consulting Profile.