HOUSTON, Texas (KTRK) -- Monday's killing of Houston police Sgt. Sean Rios marked the department's second officer killed in just three weeks. But he's also the fourth officer killed in the line of duty within one year.
We're remembering Houston officers, as well as surrounding area officers and deputies, who were killed in the line of duty.
Houston police Sgt. Christopher Brewster was killed in December 2019 while responding to a domestic disturbance call on Avenue L. When Brewster arrived at the scene, the couple had left the location, but were found walking in the 7400 block of Avenue L. Brewster came under fire as soon as he tried to exit his patrol cruiser, according to Houston Police Chief Art Acevedo.
Arturo Solis, 25, is the suspected shooter, Acevedo said. Solis has a lengthy criminal history, including a charge of assault causing bodily injury.
Brewster was hit multiple times but still managed to draw his weapon and radio a description of the suspect to other responding officers.
Brewster's death was the first line-of-duty fatality involving a Houston-area law enforcement officer since Harris County Sheriff's deputy Sandeep Dhaliwal was ambushed during a traffic stop in Sept. 2019.
WATCH: Remembering Chris Brewster: An officer and an athlete
HPD officer Jason Knox died in May 2020 in a police helicopter crash. Knox and HPD helicopter pilot Chase Cormier were searching the bayou for a drowning victim when their helicopter went down in Greens Bayou.
Knox was an eight-year veteran of HPD. He was a tactical flight officer who joined the Air and Marine Division of HPD in January 2019. Prior to that, Knox served as a Harris County deputy constable.
WATCH: Some of the moments remembering Houston Police Officer Jason Knox
A 41-year-veteran of the Houston Police Department, Sgt. Harold Preston was preparing to retire from the force this year, but his plans were shattered when he was shot and killed Oct. 20, 2020.
Preston and officer Courtney Waller were responding to a domestic violence call in southwest Houston. When Preston, Waller and another officer arrived to the scene, the estranged wife of the suspect, identified as 51-year-old Elmer Manzano, told them she was moving out and wanted to retrieve items from the apartment.
The woman said the door was locked and Manzano wouldn't let her in. Officers spoke with her for an hour.
Manzano's 14-year-old son, who was with the woman in the parking lot, managed to unlock the door and open it.
The son saw that Manzano had a gun and told officers. That's when Manzano fired multiple rounds, hitting Waller and Preston, Acevedo said.
Waller was hit in the shoulder area and a bullet was embedded in his spine. Preston died after being shot multiple times. He was laid to rest on Oct. 30, 2020.
WATCH: Fallen HPD sergeant laid to rest in north Texas
On Monday, Nov. 9, 2020, Sgt. Sean Rios was headed to the airport when he was involved in a shootout with a suspect in north Houston.
After being shot, Rios ran into the Taj Inn & Suites motel looking for help and collapsed. He was declared dead at the scene.
A witness at the scene who heard the gunshots told ABC13 he saw the officer running toward the motel searching for help.
"He was just bleeding everywhere, all over, and just not running right. He entered the office at the motel and he collapsed right in there," the witness said.
Rios was a 25-year member of the Houston Police Department. He leaves behind four kids ages 17, 14, 12 and 9; as well as his parents, a brother, and two cousins, who are HPD detectives.
WATCH: HPD Sgt. Sean Rios' body arrives at medical examiner's office
But Houston police were not the only agency mourning a tragic death of their own.
HFD arson investigator Lemuel Bruce
In October 2020, the Houston Fire Department lost an arson investigator who was conducting surveillance during an arson investigation in the 2100 block of W. 18th St. near Watercrest.
Authorities say Lemuel Bruce got into a confrontation with a suspect where they exchanged gunfire. The suspect died at the scene. About an hour later, Bruce died from his injuries at Memorial Hermann Hospital.
This is the first time an HFD arson investigator has been killed in the line of duty.
This is also the fourth HFD line-of-duty death since July, with the department losing three of its members to COVID-19 and complications from the illness.
WATCH: HFD arson investigator dies after shooting with suspect in NW Houston
Outside of Houston, these surrounding law enforcement agencies also mourned losses of their members.
A 10-year veteran of the Harris County Sheriff's Office, Sandeep Dhaliwal died September 2019, after he was shot during a traffic stop in northwest Harris County.
The deputy belonged to the Sikh faith, the fifth largest religion in the world, whose members commit to equality, service and justice. Before he donned his shield and uniform, Dhaliwal was an entrepreneur who sold a lucrative business in order to go into law enforcement.
Dhaliwal leaves behind a wife and three children.
The suspect accused of shooting Dhaliwal to death has been charged with capital murder of a police officer.
WATCH: Dhaliwal was a trailblazer who spoke for need to support law enforcement after Deputy Goforth's murder
In December 2019, Nassau Bay police Sgt. Kaila Sullivan was one of multiple officers attempting to arrest a man wanted on warrants when she was hit and killed by the suspect's vehicle.
While trying to arrest the driver, police said the suspect fought with officers and was able to break free, re-enter the vehicle, and hit Sullivan as he drove away.
Sullivan was taken to HCA Clear Lake Hospital by ambulance, where she died.
WATCH: Community says goodbye to Nassau Bay Sgt. Kaila Sullivan