The San Bernardino County District Attorney’s Office has completed its review of the officer-involved shooting which occurred on June 29, 2020. This incident happened in the city of Montclair and involved the Pomona Police Department. The shooting was investigated by the Montclair Police Department.


On June 29, 2020, at about 3:47 pm, police officers from the Pomona Police Department were on the I-210 Freeway in Pomona. They were directed there by a Pasadena Police Department’s helicopter crew, which was following a gold Kia Optima believed to be driven by a homicide suspect, Nick Costales. Mr. Costales had admitted to killing his mother in Fresno, California, and was traveling south through the state. Assisting the Pomona Police Officers were officers from the California Highway Patrol (CHP). All officers were informed Mr. Costales might be armed with a handgun.

Pomona Police Officers Cynthia Burciaga and Sean Gonzalez were directed to the Kia, which was in the freeway’s eastbound #3 lane. The officers drove behind the Kia. They turned on their emergency lights and siren to stop the Kia. Pomona Police Sergeant William Knight and Officers Vaneric Mendoza and Wallace Gonzalez were behind Officers Burciaga and Gonzalez’s police car. California Highway Patrol (CHP) Officers Thomas Alaimo and Cesar Banuelos, each driving separate police cars, followed the Pomona Police Officers.

Mr. Costales exited the freeway at the Monte Vista Avenue offramp in the city of Montclair. He turned south on Monte Vista Avenue and stopped along the west curb at about 3:52 pm.

Officer Burciaga stopped her police car about one car-length behind Mr. Costales’ Kia. Sergeant Knight stopped his police car along the side of Officer Burciaga’s car. Officer Gonzalez stopped his police car behind Officer Burciaga’s and Sergeant Knight’s cars.

As soon as Mr. Costales’ Kia came to a stop, Mr. Costales immediately opened his driver’s door and quickly exited, facing the officers. He immediately raised a handgun and began firing at the officers. Mr. Costales first round struck Officer Burciaga’s police car.

Mr. Costales moved his arms left to right and back again, in a horizontal sweeping type motion, while firing his handgun. Officers Burciaga, Sean Gonzalez, Mendoza, and Sgt. Knight quickly exited their cars, obtained cover, and fired back at Mr. Costales.

While the officers and Mr. Costales were exchanging gunfire, CHP Officer Alaimo stopped his police car behind and slightly east of Sgt. Knights car. A witness had stopped their car behind Officer W. Gonzalez’s police car, and the witness was “ducking” behind his car. CHP Officer Banuelos stopped his police car behind Officer Alaimo’s police car. He saw the other officers were behind their police cars taking cover from Mr. Costales’ gunfire.

Mr. Costales continued shooting at the officers until the officers’ return fire eventually struck him. Mr. Costales fell to the ground but began getting back up with his gun. The officers fired at Mr. Costales until he was down on the ground and no longer shooting.

The officers took Mr. Costales into custody. He was treated and transported by emergency medical personnel to Pomona Valley Medical Center, where he underwent surgery for his injuries. Mr. Costales died at 8:20 pm.


The Montclair Police Department investigated this shooting. A review of the investigation, reports, evidence, and statements was completed by the San Bernardino County District Attorney’s Office.

Based on the facts presented in the reports and the applicable law, our office concluded Sergeant Knight, Officer Sean Gonzalez, Officer Burciaga, and Officer Mendoza’s use of lethal force was a proper exercise of their rights of self-defense and defense of others, and therefore their actions were legally justified. The additional officers at the scene did not use lethal force as their particular positions at the time of the shooting did not provide them with a lawful and safe manner in which to render such force.


By providing a thorough explanation to the community regarding the review of officer-involved shootings, it is the intention of District Attorney Jason Anderson and the San Bernardino County District Attorney’s Office to maintain the community’s confidence and trust in its law enforcement officers and district attorney’s office.

Key Points of This Incident

  • Mr. Costales had murdered his mother in Fresno, California.
  • Mr. Costales had stolen and drove his mother’s Kia away from the scene.
  • Mr. Costales unlawfully possessed a loaded handgun.
  • Using search warrants, police officers were able to locate Mr. Costales driving on a freeway.
  • Police officers conducted a traffic stop to safely take Mr. Costales into custody.
  • Mr. Costales fired his handgun at the police on a public roadway occupied by uninvolved people.
  • Mr. Costales’ unsafe actions were stopped by the police returning gunfire and striking Mr. Costales.

Police officers are trained to respond to situations such as these, and they continually update their training as new situations and techniques are identified.

Additionally, police officers have equipment on their belts, vests, and vehicles, which they use to complete their duties.

Police officers are expected and authorized to use the equipment to protect themselves and others from suffering injuries or death. To some, watching a police officer using physical force against another person can be upsetting or disturbing.

Police officers prefer to use the least amount of force, whether it be their mere presence or verbal commands, to diffuse situations. However, there are situations, such as this incident, in which lethal force is necessary for the community and police officers’ safety.

In rapidly tense situations, officers do not have a great deal of time planning, revising, or analyzing a situation, such as readers of this article. When a situation evolves, officers must make the best decisions possible to protect and save lives in a condensed amount of time.

The community expects that the people they call upon to protect them, which is the police, will not back down, be intimidated, or run scared when danger presents itself.

On June 29, 2020, Mr. Nick Costales decided to travel on the I-210 Freeway in the area of the city of Pomona after he had murdered his mother in Fresno, California.

After police officers had turned on their emergency lights and siren to perform a traffic stop on Mr. Costales, it was Mr. Costales who decided to stop the stolen Kia he was driving along the curb of a public roadway.

Mr. Costales decided he was going to either kill or injure the police officers who were stopping him. Mr. Costales exited his Kia and faced the officers. Mr. Costales chose to fire his handgun at the officers and the witness hiding behind a vehicle.

Mr. Costales’ deadly and unsafe decisions only came to an end after being stopped by the police officers shooting and injuring him.

There is an extremely high probability this officer-involved-shooting would not have happened had any of the following occurred:

  • Mr. Costales had not murdered someone
  • Mr. Costales had not stolen a vehicle
  • Mr. Costales did not have a handgun
  • Mr. Costales had not fired his handgun at police officers


The San Bernardino County District Attorney’s Office’s Shooting Review Team responded to the scene after it was rendered safe by law enforcement.

Upon taking office, District Attorney Jason Anderson wanted a dedicated team of trained and experienced deputy district attorneys and investigators to review these shootings and respond to the scene of shootings.

Please visit to learn more about this team.

As the district attorney’s office, we realize the entire community is affected when force is used by peace officers, regardless of the situation or circumstances. Our responsibility is to ensure that all parties involved in cases such as the one involving Nick Costales acted lawfully.



View San Bernardino County District Attorney’s Public Release Memorandum: Nick Costales