Darrel Lambert currently works as a detective for one of the largest police departments in Texas, investigating crimes against children. He has worked in his department for over 19 years, more than 8 as an investigator. Darrel has hundreds of hours in the interview room with suspects for crimes ranging from simple assaults up to the continuous sexual abuse of children and even murder. Darrel has a bachelor’s degree with honors from Wesleyan University in Middletown, CT. He is a certified TCOLE instructor. Darrel has received awards including Lifesaving, Meritorious Service, Honorable Conduct, and others while serving at his department.

Darrel had his book, Fundamentals of Interviewing and Interrogation, published by Routledge in late 2025. It is available on Amazon.

Darrel writes a popular blog on interview and interrogation that is read by many in the field. https://lewispurdy.substack.com He and Val are the primary instructors for interview and interrogation at their department.

Valentin “Val” De Los Santos currently works as a Sergeant for one of the largest police departments in Texas, currently assigned to patrol division. He has worked at his department for over 18 years, more than 8 as an investigator. Val has hundreds of hours in the interview room with suspects for crimes ranging from aggravated assaults, aggravated robberies, homicides, human trafficking up to the continuous sexual abuse of children. Val is a graduate of Texas State University. He is a certified TCOLE instructor. Val has served in the United States Navy active duty and reserves for over 30 years. https://www.linkedin.com/in/valentin-d-789a3330/ He and Darrel have instructed as subject matter experts at the international Crimes Against Children Conference in 2022-2026.