LOS ANGELES >> Gunmen fired dozens of bullets into an SUV in a “brazen assault” that killed a 12-year-old boy and wounded his stepmother and a 9-year-old girl on a nearby school playground, the Los Angeles police chief said Tuesday.

At least two attackers and at least one “very powerful” gun were used in the Monday afternoon attack outside Wilmington Park Elementary School in the southern Wilmington neighborhood, Chief Michel Moore said. He called the attack “purposeful” but there was no immediate word on a motive.

“This was a brazen assault in the middle of the day that, whether it was targeted in a pre-emptive manner or a premeditated manner or spontaneous, I just know that the amount of violence was just … It just boggles your mind when you think about an afternoon outside of a school,” Moore said.

The Los Angeles County coroner on Tuesday identified the boy as 12-year-old Alexander Alvarado. Authorities initially said the boy was 13.

He was shot in the head, Moore said, while his stepmother was shot in the stomach but was able to drive away to safety. The boy’s 10-year-old brother was in the SUV’s backseat and wasn’t wounded.

The chief said he believes the 9-year-old girl was shot in the back by a stray bullet as she was on a playground for an after-school program.

Alexander “was very innocent, very sweet and loving child,” said his mother, Jenny Romero.

“It’s the worst news a mother could ever get. The worst. I went crazy,” Romero told KCBS-TV.

Romero said her wife was picking up the boy’s brother from an after-school program when a teenager suddenly appeared and opened fire on the car, wounding the woman.

“She said it came so quick. She didn’t even know what to do, she just stepped on that gas pedal real quick, but it was too late,” Romero said.

Romero said she had no clue why someone would want to hurt her family.

The conditions of the stepmother and the girl weren’t immediately released.

No arrests had been made and Moore said he didn’t have a description of the attackers.

However, “easily” dozens of bullets were fired and that indicates that the attack was purposeful, the chief said.

Moore said the shooting highlighted an increase in gun violence in the city over the past couple of years. The chief said 27 people were shot in the city in the past week, including 19 over the weekend.