El Dorado County District Attorney Vern Pierson has become a leading voice in law enforcement reform, advocating for ethical, science-based interviewing and interrogation methods. His journey began nearly a decade ago when he encountered the thesis of his Center for Homeland Defense and Security Master’s Program classmate Desmond O’Neill. O’Neill’s thesis, “From Third Degree to Third Generation Interrogation Methodologies: Putting Science into the Art of Criminal Interviewing,” introduced Pierson to ethical techniques that prioritize truth without coercion or deception.
Now-retired ICE Special Agent O’Neill (Master’s cohort 1505/1506, HSx 1701) introduced Pierson (Master’s cohort 1505/1506) to science-backed interview methods, sparking a collaboration that drove major reforms. O’Neill, who became involved with the High Value Detainee Interrogation Group (HIG) while writing his thesis, said the success he and Pierson attained through their collaboration at CHDS led him to introduce his classmate to the HIG.
“Vern’s role as DA, his dedication to justice, and his involvement in interviews led him to see that outdated, manipulative techniques from the 1940s were still being used—and needed to change,” O’Neill said. “He saw too many unethical, ineffective interviews resulting in false confessions and justice denied, so he launched a mission to reform California’s law enforcement interview protocols, making unprecedented progress in recent years.”
Pierson said O’Neill’s thesis provided “much-needed guidance” for the effort.
“His work in this area is a big part of what has led to what’s happening both here in California, as well as throughout the United States, and it really was based upon the connection that he and I had and working together [at CHDS],” he said. “Seeing the problem and needing a solution for it, CHDS had a big part in that.”
Previously, law enforcement training in the U.S. often included aggressive tactics involving deception and psychological pressure. As Pierson and O’Neill reviewed cold cases, they discovered that these techniques led to wrongful convictions, some later overturned by DNA evidence. This experience strengthened Pierson’s resolve to change the way law enforcement officers approach interviews. “If law enforcement officers, as community caretakers, routinely lie, how can the public truly trust them?” Pierson argued.
Known for science-backed, rapport-based interrogation techniques initially developed for counterterrorism, HIG’s methods demonstrated that truthful information is more likely to emerge from respectful, honest interactions rather than coercion. Seeing its potential for criminal justice, Pierson adapted HIG’s techniques to California law enforcement and introduced them to the California Commission on Peace Officer Standards and Training (POST), which has since adopted these methods statewide.
Today, California POST training emphasizes empathy, rapport-building, and humane practices, steering clear of deception and manipulation. This shift not only aligns with ethical standards but also leads to more reliable confessions, reducing wrongful convictions. Pierson’s commitment to this approach has made him a sought-after speaker and consultant nationwide, including training law enforcement in places like Miami, FL.
“Ethical interviewing isn’t just the right choice for communities—it’s also the most effective choice for justice.”
– El Dorado County District Attorney Vern Pierson
“Not only is there an ethical disconnect with using deception, but it doesn’t work effectively,” Pierson explains, citing HIG’s research that supports these more humane methods. He now collaborates on curriculum development across the U.S. to promote this ethical approach, demonstrating how a classroom connection with O’Neill has grown into a movement reshaping law enforcement interview and restoring public trust in justice systems.
Pierson’s work also highlights a growing recognition within law enforcement that traditional methods need a re-evaluation. For decades, tactics designed in the 1940s focused on aggressive questioning and deceptive practices, but those outdated methods often led to unreliable results, damaging community relationships and undermining trust in the justice system. Through Pierson’s initiatives, officers now learn how empathy and rapport can produce more accurate information, fostering a culture of transparency and accountability in policing.
Beyond California, Pierson has gained attention for his reform efforts and is often invited to share his insights with police departments and law enforcement agencies nationwide. By offering workshops, contributing to curriculum development, and serving as a media resource, he hopes to inspire a wider shift toward science-based interviewing practices. His message is clear: ethical interviewing isn’t just the right choice for communities—it’s also the most effective choice for justice.
