Crime Scene Investigation, Collection, Reconstruction / Cold Case Expert Witnesses: 14

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.

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

• Foundation Fingerprint Course
• Intermediate Fingerprint Course
• Advanced Fingerprint Course
• Scene Examiner
• Trained as Crime Scene Manager
• FERRT (Forensic Evidence Recovery and Retrieval Techniques) Trained

• Criminal Cases - Perform a comparison of an identified case and offer an independent analysis of the identification. Offer evidence to advise the Defense on related fingerprint matters.
• Immigration - Provide an impartial comparison of sets of fingerprints in dispute and provide an independent report into the comparison.
• Civil Cases - Assist Courts and Tribunals throughout the UK and abroad on issues involving contracts, wills and covenants.
• International Electoral Services - analyze ballot slips for duplicate or multiple thumb impressions.
• Fingerprint Development - developed fingermarks are photographed in line with published guidelines which allow for "cradle to grave" service.

Global Forensic Services, LLC (GFS) is a Forensic Consulting, Laboratory and Investigative Firm offering over 44 years of experience and training in a wide range of forensic science and private investigation disciplines.

Larry Stewart has personally examined tens of thousands of individual items of evidence from sources such as state, local, and federal agencies (e.g. Federal Bureau of Investigation, Secret Service, Bureau of Alcohol, Tobacco and Firearms, Central Intelligence Agency, and others), and foreign governments. On several occasions he has examined cases involving international disputes between governments. 

Mr. Stewart has testified as an Expert Witness in state, federal and military courts of law, as well as in foreign court systems to include; Austria, Australia, Canada, Germany, Singapore, Sri Lanka, Switzerland and Thailand. He has also testified at The Hague in the Netherlands and three times as an expert before the U.S. Congress. 

Areas of Expertise Include:

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.

Kirk DeLeeuw is a highly regarded and accomplished Forensic Biology and DNA Consultant / Expert Witness both nationally and internationally. He has over 20 years of dedicated experience in Molecular Biology and Forensic Science and is well respected worldwide.

Mr. DeLeeuw's career is defined by a deep technical mastery of DNA analysis, including specialized expertise in interpreting complex multi-contributor samples using Probabilistic Genotyping Software (PGS) such as STRmix. Mr. DeLeeuw is licensed by the Texas Forensic Science Commission. He likewise has a comprehensive understanding of FBI Quality Assurance Standards (QAS) and ISO/IEC 17025 accreditation requirements. He applies the standards through meticulous auditing of case files, bench notes, and high-volume electronic data files and images.

Litigation Support - Beyond the laboratory, Mr. DeLeeuw is a seasoned Expert Witness, qualified to provide testimony in Body Fluid Identification / Serology and DNA Analysis across numerous jurisdictions. He has provided sworn affidavits and oral testimony in federal, circuit, and district courts in many states including Washington DC, and internationally in the Royal Turks and Caicos Islands. His ability to translate sophisticated molecular biology data into clear, accessible testimony ensures that scientific integrity remains paramount during both civil and criminal litigations.

Mr. DeLeeuw maintains technical proficiency through a rigorous commitment to continuing education, frequently attending the International Symposium on Human Identification and National CODIS Conferences. His hands-on experience spans a wide array of instrumentation, including Applied Biosystems Genetic Analyzers and Hamilton robotic workstations, as well as various quantification and amplification kits. This combination of technical expertise, regulatory knowledge, and proven courtroom experience allows him to provide unparalleled oversight and analysis in the field of forensic DNA.

Areas of Expertise:

Background Experience - Mr. DeLeeuw's extensive professional background includes high-level roles across private and public sectors. As a Forensic DNA Analyst at DNA Labs International, he analyzed casework from across the United States and internationally, utilizing advanced PCR/STR-based methods and various chemistries. Prior to that, he served for nearly 20 years as a Forensic Scientist for the Michigan State Police.

Ryan Larrison is a senior forensic science and public sector executive with over 25 years of experience spanning Forensic Laboratory Operations, Quality Assurance, Firearms Examination, and large-scale Program and Systems Management within the Michigan Department of State Police.

Mr. Larrison currently serves in a senior leadership role within the Information Technology Division, where he directs a multi-million-dollar portfolio of enterprise systems, operations, and project delivery. In this capacity, he oversees complex, multi-agency initiatives, aligning technical execution with operational and investigative outcomes across multiple state departments. His work includes executive sponsorship of statewide technology programs and the coordination of vendors, stakeholders, and cross-functional leadership teams in high-risk, high-visibility implementations.

Litigation Support - Mr. Larrison serves as an expert witness in cases involving laboratory analysis or laboratory quality assurance. He has been deposed and/or testified over 200 times in the past 5 years.

Areas of Laboratory Expertise:

Background Experience - Prior to his current role, Mr. Larrison served as Assistant Division Director and Quality Assurance Manager for the Michigan State Police Forensic Science Division. In that role, he was responsible for the strategic direction, implementation, and oversight of quality systems across seven accredited forensic laboratories. He led all quality assurance activities, including training, corrective action programs, risk assessment frameworks, and accreditation compliance under ISO 17025 standards. His leadership resulted in a substantial reduction in non-conformities and sustained accreditation across all laboratory operations. 

Mr. Larrison has extensive experience as a program executive and project sponsor for complex forensic and evidential systems. He directed the statewide implementation of the Evidential Breath Alcohol Testing Program, including instrument selection, software integration, vendor coordination, and regulatory compliance, supported by a $2.5 million procurement process. He also led the development and implementation of a Forensic Genetic Genealogy program, establishing quality expectations, vendor deliverables, and investigative reporting standards.

Robert J. May has a distinguished career spanning more than 30 years, with experience in Forensic Analysis, Executive-level Management, and Quality Assurance. He is a Latent Print Examiner with nearly 25 years of experience and has been a consultant with Riley, Welch, LaPorte and Associates for roughly 20 years.

Litigation Support - Mr. May has conducted latent print casework and technical reviews across the United States and beyond, having been qualified as an expert witness across multiple jurisdictions. He provides clear, accessible expert testimony, affidavits, and consultation to attorneys, investigators, and courts, translating complex latent print, crime scene, and forensic imaging issues into opinions that can be understood and evaluated by judges and juries. Mr. May has never been excluded as an expert or from testifying as an expert witness in any County, State, Federal, Arbitration or Administrative proceeding. 

Areas of Expertise:

• The Use of Automated Fingerprint Identification Systems (AFIS)
• Fingerprint Comparison and Identification Methodology
• Digital Enhancement Techniques
• Crime Scene Processing
• Evidence Processing and Documentation Using a Variety of Physical and Chemical Techniques
• Latent Print Visualization Using Alternate Light Sources and Lasers
• Subject Matter Expert in Digital Photography (taught crime scene and general photography for multiple agencies)

In addition to technical acumen in his forensic specialties, as a Laboratory Executive, Mr. May is a recognized leader in the forensic community. He has served as a laboratory director across multiple systems, with broad knowledge of lab operations, facility design, policy development, budgeting, human resources, metrics, process evaluation, and more.

Background Experience - Mr. May has a diverse background in both forensics and law enforcement. Prior to his current position as the Crime Lab Manager for the Corpus Christi (TX) Police Department’s Forensic Services Division, Mr. May spent 26 years as a trooper with the Michigan State Police, one of the nation’s premier law-enforcement agencies. Aside from considerable knowledge of general investigations and law-enforcement operations, his deepest expertise, and greatest passion, lies with forensic science. Mr. May spent most of his career within the MSP Forensic Science Division, beginning as a technical expert in latent prints, crime scene investigation, and forensic photography. He rose to the position of supervisor in latent prints and was ultimately promoted to laboratory director at the Sterling Heights Laboratory in Metro Detroit. He retired in 2020 as a decorated command officer with multiple commendations to his name, including awards for professional excellence and lifesaving, among others.

Dean S. Molnar, Jr. is a highly trained and exceptionally experienced Firearm and Tool Mark Examiner, Crime Scene and Firearms Trajectory Analyst, and a proven leader in the field of Forensic Science Operations and Quality Assurance. Mr. Molnar has over 25 years of experience as a certified law enforcement officer and State Trooper, and over 17 years of experience serving as a firearm and tool mark examiner, firearms and tool mark unit supervisor, and laboratory director with the Michigan State Police (MSP) Forensic Science Division.

Litigation Support - Mr. Molnar's experience as a forensic firearm and tool mark examiner includes recognized expert testimony in over 140 criminal cases in both state and federal courts involving both firearms and tool mark identification, crime scene investigation, and shooting reconstruction.  He has personally processed over 60 homicide scenes during his career, including scenes involving shooting reconstruction, photography, and documentation.

Areas of Expertise:

• Firearms function, operability, alterations, defects, conversions, modifications, accidental discharge
• Cartridge manufacture and source determination of ammunition components
• Shooting scene (trajectory) reconstruction
• External and/or terminal ballistics calculations and determinations of the projectile’s trajectory, ricochet, penetration, etc
• Distance determinations (muzzle-to-target determinations) from gunshot residue patterns or shot pellet patterns
• Serial number restorations (firearms, motorcycles and other vehicles, bicycles, etc.) – anything with an identifying characters, numbers or markings that have been obliterated either intentionally or by wear or corrosion

Background Experience - Mr. Molnar’s leadership experience has included firearms unit supervisor duties at three different laboratories. He currently serves in a key role as the Laboratory Director at the Michigan State Police-Lansing Laboratory where he is specifically assigned as the operations director for pattern disciplines.

Mr. Molnar also has over seven years of quality assurance experience as an ANSI National Accreditation Board (ANAB) assessor. His years of experience include almost 15 years of ongoing training within an extremely professional and accredited crime scene processing program at MSP, along with even more specialized training in firearms trajectory analysis. Mr. Molnar holds a Bachelor of Science in Fire Science and a Bachelor of Science in Criminal Justice from Lake Superior State University. He is a long-time member of the Association of Firearms and Tool Mark Examiners (AFTE) and is also a member of the American Society of Crime Laboratory Directors (ASCLD).

Lawrence R. Porte is a nationally and internationally recognized Investigative Analysis Expert and Trial Assist Analyst with more than forty (40) years of experience in federal law enforcement, protective intelligence, targeted violence assessment, aviation security, and criminal investigations.

Mr. Porte's distinguished career spans service with the United States Secret Service, the Department of Homeland Security, the Transportation Security Administration, higher education, and municipal law enforcement, giving him rare depth in both operational and analytical aspects of complex investigations.

 Litigation Support - Mr. Porte is widely respected for his ability to assess investigative integrity, identify behavioral warning signs, and provide clear, well-supported analyses. His current consulting work focuses on investigative case review, litigation assist support, and threat assessment for attorneys and institutions confronting high-risk or procedurally complex matters.

Areas of Expertise:

Background Experience - During his federal career, Mr. Porte held senior leadership positions with the United States Secret Service and later served as Special Agent in Charge for the Transportation Security Administration, where he directed investigative operations across a 14-state region that included approximately 110 federally protected airports. In that capacity, he supervised criminal investigations, cargo security matters, and internal misconduct inquiries, while also helping develop the TSA’s first Workplace Violence Policy and the agency’s Integrity Test Program aimed at combating theft and misconduct in airport environments.

Earlier in his career, Mr. Porte served on the White House Presidential Protective Division and was a member of the first White House Counter Assault Team, experiences that placed him at the center of some of the nation’s most sensitive protective and intelligence operations. He also opened and managed the Saginaw Resident Agent Office and later served as Special Agent in Charge of the Detroit Field Office, with oversight of additional Michigan offices.

Mr. Porte’s national and international recognition is further reflected in his participation in significant protective intelligence and investigative matters, including a threatened assassination plot involving Indian Prime Minister Rajiv Gandhi and an operation connected to extremist networks and coordinated activity extending into Canada. 

George Schiro is a DNA Technical Leader - Forensic Scientist. His duties include incorporating the DNA Advisory Board (DAB) standards, accountability for the technical operations of the lab, conducting DNA analysis using the 13 STR core loci and Y STR in casework, DNA research, forensic science training and crime scene investigation.

Mr. Schiro has worked over 3500 cases and has qualified as an expert over 175 times in 31 Louisiana parish courts, Arkansas, California, Florida, Mississippi, Missouri, Nevada, New York, Texas, West Virginia, federal court, U.S. court-martial, and two Louisiana city courts. Has also consulted on cases in 29 states.

Qualified as an Expert in the Following Areas:

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
• Sex Trafficking and 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.

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

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: 

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: