The Principis Team
For context on how Principis Group’s work has evolved over time, see Our Shift in Focus.
Daniel J. Zehnder
Founder & President
Dan Zehnder is the Founder and President of Principis Group Inc., an independent law enforcement advisory firm specializing in body-worn camera governance, supervisory review, policy development, and organizational risk management for public safety agencies and government partners.
Principis Group was founded in 2015 to assist law enforcement agencies in addressing the operational, policy, and accountability challenges associated with body-worn camera programs. As these challenges have expanded, the firm evolved beyond implementation support into a broader governance and advisory role—helping agencies strengthen supervision, align policy with practice, and sustain defensible oversight in increasingly complex operational and public environments.
Today, Principis Group works with law enforcement agencies, local and state governments, and select private-sector partners, supported by a bench of experienced advisors across multiple law enforcement disciplines. Engagements commonly involve body-worn camera program governance, supervisory review operating models, use-of-force and duty-to-intervene assessments, training program development, investigations, search warrant services, pursuits, narcotics operations, civil unrest response, police–government relations, and organizational risk management.
Dan retired as a Captain from the Las Vegas Metropolitan Police Department after 22 years of service. He served as the department’s Body-Worn Camera Program Manager for two and a half years, with responsibility for the planning, deployment, operations, and ongoing management of one of the nation’s largest body-worn camera programs.
Through Principis Group, Dan has advised and trained more than 200 law enforcement agencies, government entities, and technology organizations nationwide. He is a frequent presenter on body-worn camera governance, supervision, and accountability. Since 2015, he has served as a Subject Matter Expert for the Bureau of Justice Assistance Body-Worn Camera Training and Technical Assistance Team, managed by CNA Corporation. He is also a member of CNA’s Center for Justice Research and Innovation Project on American Justice, has served as a body-worn camera grant peer reviewer for the Office of Justice Programs, and is a member of the Bureau of Justice Assistance National Training and Technical Assistance Center’s Body-Worn Camera Speakers Bureau.
Prior to his law enforcement career, Dan served 21 years in the United States Army. He holds a Bachelor of Science degree from the University of Louisville and a Master of Arts degree from The George Washington University.
Christopher Darcy​
Senior Law Enforcement
Advisor
​Chris retired as Undersheriff of the Las Vegas Metropolitan Police Department. He has over 32 years of experience in law enforcement operations. Chris has held leadership positions in a variety of law enforcement disciplines including investigations, homeland security and counter-terrorism. This experience has helped him attain a vast, and unique, level of knowledge and understanding in many areas of police and corrections work such as patrol operations, use of force, duty to intervene, search warrant service, pursuits, in-custody deaths, recruiting, training, policy development and implementation, and civil unrest. Chris is also Founder of Fairfax Consulting Group, LLC
​
Tom Roberts
Senior Advisor
Oversight, Accountability, & Public Policy
​
Tom retired as Assistant Sheriff from the Las Vegas Metropolitan Police Department. He has been a dedicated public servant to his country and the state of Nevada for the past 38 years: first as an Airman in the U.S. Air Force and then as a member of the LVMPD and, most recently, as a member of the Nevada State Assembly. During his tenure at LVMPD, Tom worked in a number of capacities, including: DEA Interdiction Task Force Sergeant, Hostage Negotiator, Director of Intergovernmental Services, Patrol Bureau Commander, Captain of the Office of Internal Oversight, Deputy Chief of Patrol and of Investigations.
As Director of Intergovernmental Services, Tom served four years representing LVMPD and lobbying at Clark County, City of Las Vegas, Nevada Legislature/Governor and Nevada’s Federal delegation. In addition, he worked collaboratively in lobbying with Major Police Chiefs, Major County Sheriffs and Nevada Sheriffs and Chiefs Associations. As a member of the Nevada Assembly, Tom serves on numerous legislative committees.
Tom is also Managing Partner of Meridian Nevada, a political and strategic consulting service.
​
Laz is a retired Assistant Sheriff of the Las Vegas Metropolitan Police Department. Throughout his 33 year career, he served as a patrol officer navigating his way to SWAT crisis negotiator, narcotics detective, robbery detective, promoting to sergeant then to lieutenant
overseeing the Criminal Intelligence Section. He was promoted to captain and became the commander of the Theft Crimes Bureau and, subsequently, the Downtown Area
Command. He was appointed to Deputy Chief of the Investigative Services Division (ISD), responsible for five bureaus: Criminalistics, Homicide and Sex Crimes, Major Violators/Narcotics Crimes, Theft Crimes, and Gang/Vice.
He served as Parliamentarian of the National Latino Peace Officers Association; executive board member of the Rocky Mountain Information Systems, and High Intensity Drug Trafficking Area. On appointment to Assistant Sheriff, he oversaw four divisions: Homeland Security, Investigative Services, Support, and Business and Technology.
Lazaro Chavez
Senior Advisor
Investigations, Intelligence,
& Operational Oversight
​
​Damon Mosler was a San Diego County Deputy District Attorney for over 29 years. He retired in 2022 as the Chief of the Economic Crimes Division. He also served as Division Chief of both Narcotics and Special Operations, as well as being the Law Enforcement Liaison for the San Diego County Sheriff’s Department. Mr. Mosler is a nationally recognized expert in body-worn cameras (BWC), digital evidence management (DEM), case preparation, predator/club drugs, informant handling, and 4th amendment law. Mr. Mosler served as a consultant for the Bureau of Justice Assistance BWC Training and Technical Assistance Team, managed by CNA, for eight years. He also worked for Axon Justice Solutions on BWC’s and DEM.
​
Damon Mosler
Senior Advisor
Prosecution, Digital Evidence,
& BWC Governance
​