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Sergeants (Day Shift)
Mercedes Martinez-Lopez - CORE
Sgt. Martinez-Lopez began her career with the Police Department in December 1994. While a campus officer, she introduced RAD (Rape Aggression Defense program, a Self Defense Program for women, giving the students tools needed in order to prevent or escape harmful situations. After eighteen years in campus operations, she transferred to patrol Division. Being assigned to power shift, she was involved in a variety of community engagements, and introduced presentations covering different topics to the HISD community. She promoted to Sergeant on November 2014, and is currently assigned to second shift patrol division.
Sergeant Martinez-Lopez holds a Master TCOLE Peace Officer License, Associate of Applied Science Degree, Basic Instructor Certificate and over 3,500 hours of TCOLE training.
Vanessa Losey - Patrol
Native Texan Vanessa Losey is a sergeant for HISD Police Department. Prior to becoming a sergeant, Officer V. Losey was a member of HISD PD C.O.R.E (Community Outreach Responsive Engagement) that provided opportunities for positive interactions with HISD students, parents and faculty and all HISD PD staff to have a large impact in changing the dynamics of the relationship between the police and the community. Sergeant V. Losey joined the HISD Police Department in 2015 where she has served as a Campus Officer (Sharpstown High School), certified TCOLE, D.A.R.E and T.A.P.S Instructor. In her free time, Losey enjoys spending time with her family, traveling and taking pictures of her dog Lola.
Sgt. V. Losey's favorite quote:
“If you can’t fly then run, if you can’t run then walk, if you can’t walk then crawl, but whatever you do you have to keep moving forward.”
-Dr. Martin Luther King Jr.
Karl Brown - Patrol/ERT
I am a native of Houston, Texas and a 1984 graduate of Charles H. Milby Sr. High School. Immediately after graduation, I enlisted in the United State Marine Corps to proudly serve my country. After completing basic training at MCRD San Diego, California my first parent command was in the West Pacific. Between numerous deployments I was assigned to the 9th Engineering Support Battalion in Okinawa, Japan where I studied Shorin-Ryu Karate under the linage of the Shimabukuro family. As time progressed, I continued to study and become increasingly proficient in self-defense, crime prevention, and tragedy avoidance tactical systems such as:
- The United States Marine Corps Linear Infighting Neural Engagement Combat System
- The Israeli Krav Maga Defense System Law Enforcement Instructor Program (Santa Monica, California)
As a resident of Southern California, I had the unfortunate experience of witnessing multiple acts of aggressive criminal behavior to include the thoughtless and senseless shooting of a 14-year-old female. The fatal incident eventually became the primary driving force that motivated me to become a law enforcement officer help with thew protection of kids.
I attended Gus George Law Enforcement Law Enforcement Academy in Fort Bend, Texas and began my career in law enforcement shortly afterwards. To name a few of my tactical related certifications to date please view below:
- 18-year police veteran/Master Peace Officer
- L.E.R.R.T. Instructor (Advanced Law Enforcement Rapid Response Training)
- L.I.C.E. Instructor (Alert Lockdown Inform Counter Evacuate)
- Homeland Security Active Shooter Instructor
- Force on Force Simunitions Instructor
- Dignitary Protection Instructor
- E. Firearms Instructor
- Tactical Cuffing, A.S.P. Baton, and Oleoresin Capsicum Instructor
- Aikido based Rape Aggression System Program Instructor
- Taser Instructor
Over the years I have come to believe that we allow ourselves to become part of the problem when we do not allow our skills to be used as part of the solution. I agree that it is necessary for a safe environment to exist for the teachers to teach, and students to learn.
James Hayes - Training
Sergeant Hayes began his career with the HISD Police Department in 2014 as a campus officer assigned to Evan E. Worthing High School. He has experience in campus operations, patrol operations, criminal investigations, and currently serves as the training coordinator.
Sergeant Hayes holds an Advanced Peace Officer certification and is certified with the Texas Commission on Law Enforcement in many different areas. Prior to joining HISD Police Department, he was employed with the Texas Department of Criminal Justice as a Correctional Officer and served in supervisory roles.
Hayes earned a bachelor’s degree in Interdisciplinary Studies from the University of Houston-Downtown as well as a certificate of Leadership.
Denise Royal - Patrol
Sergeant Denise Royal began her career with Houston Independent School District in 1999 as an educator. In 2007 she enrolled in the Police Academy at HCC and began her law enforcement career with Houston ISD Police Department in January 2008. Sergeant DA Royal currently holds Field Training Officer, Mental Health, Peer Mediation, Telecommunications, SAFVIC, and Master Certifications with TCOLE. Sergeant DA Royal currently oversees First Shift Patrol Operations.
Tridung Tran - K9
Since 2008, Sergeant Tridung Tran has been with the Houston ISD Police Department. He was the inaugural group of applicants selected to be part of the Houston ISD Police Department "Police Cadet" program. The program allows Houston ISD Police to sponsor an individual with salary and tuition for the police academy program at the University of Houston- Downtown Criminal Justice Center. Due to the program's success, the program has paved the way for additional groups of individuals selected to become part of the Houston ISD Police Department. After completing the program and Field Training Program, Sergeant Tran was assigned to campus operations and worked several campuses.
After some time in Campus Operations, Sergeant Tran was transferred to patrol operations and served on 2nd shift patrol for an extended period. During that time, Sergeant Tran was a "zebra" unit was assigned to investigate traffic accidents involving HISD vehicles and traffic enforcement in school zones. While serving on second shift patrol, his unit earned the Unit Citation of the Year Award and became a Field Training Officer.
In 2013, Sergeant Tran was promoted and assigned to First Shift patrol. Sergeant Tran worked on various assignments during this time, including CALEA, special project, record management system, report writing, grant proposal, instructor, and K9 Supervisor. Sergeant Tran graduated from Leadership Command College and currently supervising and leading Patrol, K9, and CALEA.
Sonia Quintanilla - IAD / Investigations / GSU
Sergeant Quintanilla attended the University of Houston Downtown Police Academy where she received three Academic accommodations and two Physical Training accommodations.
Before joining the Houston ISD Police Department, Sergeant Quintanilla was a Police Chaplin for the Pearland Police Department.
Sergeant Quintanilla is an advanced peace officer and has been a sworn member of the Houston ISD Police Department since 2013. During this time, she has been assigned to campus operation, where she became certified in Field Training, Police Bicycle Certification and S.F.S.T.
In addition to the primary duties, Sergeant Quintanilla served as a detective in criminal investigation division where she was certified in Child Abuse Prevention/Investigation, Technic Interviewing and Interrogation, Background Investigations, Crime Scene Investigations, Criminal Investigation, and Special Investigator.
June of 2018 Sergeant Quintanilla was certified as in Internal Affair investigator, she was then assigned to the Internal Affairs Division. Sergeant Quintanilla was honored with the Certificate of Appreciation Impact Award from HISD customer Service.
In December 2018 Sergeant Quintanilla was promoted to Sergeant and was assigned to the East District where she supervised over 20 officers. In 2019 she was assigned to Internal Affairs Division where she served as Sergeant over this Division. As of 2021 Sergeant Quintanilla, has been assigned to Criminal investigation where she supervises the direction of the detectives.
In addition to the 2018 certificate of Appreciation impact Award she has been honored to receive the Unit Citation Award 2016, Unit Citation Award 2018, and the Certificate of Appreciation 2018.