(KRON) — A San Jose Police Department officer was killed after being struck by a vehicle on Saturday night, the department said. The officer, who was with a colleague on the scene, was conducting a traffic stop in South San Jose when the vehicle struck both of them.

The other officer who struck was taken to the hospital with “major injuries, ” but she is expected to survive, SJPD said.

Both victims were Community Service Officers (CSOs), who are deployed to respond to “lower priority” calls for service, which include calls for burglary, petty theft, vandalism, non-injury traffic collisions, etc.

The driver of the vehicle is believed to have been under the influence of alcohol at the time of the crash, according to SJPD. The suspected drunk driver was arrested for driving under the influence.

The department will continue to investigate this “unimaginable incident.”

“Our entire police family is heartbroken by this line of duty death, and our collective arms are around his family, friends, and teammates as we all cope with this painful incident,” the department wrote in a social media post.

San Jose Mayor Matt Mahan said this “selfish, reckless act will not go unpunished.”

Our city mourns the tragic loss of one of our Community Service Officers and severe injuries sustained by another CSO in the line of duty. Each day, our officers place themselves in harm’s way to fulfill their solemn oath to protect and serve us—they are truly heroes. My prayers are with these two CSOs, their families, and our entire police department in this devastating moment, and I assure you that this selfish, reckless act will not go unpunished.

San Jose Mayor Matt Mahan

The department says more information will be released when a press conference takes place at SJPD’s headquarters Monday afternoon.

This story will be updated.