Riverside, Aug. 13 -- A man whose truck was being impounded suddenly grabbed a rifle and opened fire, killing a California Highway Patrol officer and wounding two others before he was killed, authorities said.

Other drivers ran for cover and two people were slightly injured as dozens of bullets flew shortly after 5:30 p.m. Monday just off a freeway in Riverside, east of Los Angeles.

"We don't know his motive for this crime," Riverside Police Chief Sergio Diaz said. Investigators were still gathering evidence at the scene Tuesday morning.

KABC-TV reported that a man identified the shooter as his son, Aaron Luther, 49, of neighboring Beaumont.

A CHP officer was doing paperwork to impound the pickup truck when the man reached in, grabbed...