Tyler PD Lieutenant Promoted to Assistant Chief

On Monday, Feb. 23, Lieutenant Jon Thornhill was promoted to the rank of Assistant Chief in a ceremony attended by friends, family, and co-workers. In his new role, he will supervise the Investigative Division.

Assistant Chief Thornhill said, "I am truly honored to be able to serve with the men and women of the Tyler Police Department who work continuously to improve the quality of life in Tyler."

Jon Thornhill was hired by the Tyler Police Department in May of 1996. After attending the police academy, Jon worked in the patrol division until November of 2001, when he was assigned as a Crimes Against Children Investigator at the Children's Advocacy Center of Smith County. Jon served as an investigator at the CAC for five years.

He was selected to attend the Texas DPS Polygraph School in Austin. Upon returning from this school, Jon completed his internship as a polygraph examiner, assigned to the Youth Crimes/Forgery Division.

In 2008, he was promoted to the rank of Sergeant and was assigned to the Integrity Division as an audit and inspections supervisor. In 2009, Jon was assigned as the Supervisor of the Integrity Unit. Jon worked in the Integrity Unit until April of 2016, when he was promoted to the rank of Lieutenant.

As a Lieutenant, Jon has held supervisory positions in both the Patrol and Support Services Divisions. Jon served as the department's accreditation manager from January 2022 until the close of the accreditation cycle in January 2026.

Jon was selected to attend the FBI National Academy in Quantico, Virginia, where he graduated with Session 287 in September 2023.

Jon is currently enrolled in the Law Enforcement Management Institute of Texas program and is scheduled to attend the second module in April of this year.

Jon holds a Master Peace Officer Certification and is a TCOLE instructor. He is a Licensed Polygraph Examiner and has served for several years as a board member and an officer for the Texas Association of Law Enforcement Polygraph Investigators. He earned a Bachelor of Business Administration from UT Tyler.