Police on Tuesday were investigating why a man suddenly opened fire during a traffic stop near a freeway in Riverside, California, killing a patrol officer, wounding two others and sending drivers fleeing as bullets flew.

“We don’t know his motive for this crime,” Riverside Police Chief Sergio Diaz said. The suspect, whose truck was being impounded when the incident occurred Monday evening, died at the scene, police said.

Family members identified the deceased California Highway Patrol officer as 33-year-old Andre Moye, according to KABC-TV. Debbie Howard, a family member of Moye, told NBC4 Moye was a good person and loved his job.

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“I’ve been knowing him since he was a baby,” she said in tears. “I don’t understand. I just don’t understand.”

CHP Commissioner Warren Stanley expressed his condolences in a tweet. “I am devastated by the tragedy that unfolded earlier in Riverside,” he wrote.

Diaz called the incident “a long and horrific gun battle.” 

The patrol officer was doing paperwork to impound the pickup when the suspect reached in, grabbed a rifle and fatally wounded the officer, authorities said. Police did not immediately say what prompted the officer to stop and impound the truck.

Jennifer Moctezuma, 31, of Moreno Valley told the Los Angeles Times she was driving home with her 6-year-old twins when a bullet pierced her front windshield.

Charles Childress, 56, a retired Marine from Moreno Valley who was in the car behind Moctezuma, helped the family crawl to the bottom of a bridge to hide, the Times reported. “He’s my hero,” Moctezuma said.

KABC-TV reported that Dennis Luther of Riverside identified the gunman as his son, Aaron Luther, 49. Luther said he watched the shootout on television. 

“It’s hard. I love him. And I’m sorry for the policeman,” he told KABC-TV. “I’m devastated. I just can’t believe it.”

Riverside shootout: California Highway Patrol officer killed, 2 others injured

Luther said his son served prison time for attempted murder but was released more than a decade ago. He said he didn’t know how his son had access to a gun, which is illegal for felons to possess. 

He said his son recently appeared depressed and had knee pain and marital problems. But his son was devoted to his two children and a stepchild, he said. 

“He lived for his kids. That’s what motivated him,” Luther said. “So I don’t know what overcame him. I mean, I wish I did know.”

Contributing: The Associated Press