A street maintenance worker who had reportedly been reprimanded for coming in late shot and killed his boss and another employee, authorities said.

The suspect, who was not immediately identified, then drove himself to a police station and surrendered Thursday night. Police found an AK-47 (search) rifle in his car.

The Los Angeles Times quoted sources as saying that the man had been admonished for being late Thursday morning, and the dispute escalated throughout the day. The man left work in the afternoon and came back with a gun, police said.

The victims had worked for the city's Bureau of Street Services for more than 20 years, police said.

Many street services workers have been working 12-hour days to deal with cleanup and repairs from the storms that have been pounded Southern California in the past week, Mayor James Hahn (search) said.

"It's been a very tough week, a very emotional week," Hahn said. "It doesn't seem like any issue that arises in the workplace should result in violence. It's totally unexpected."