GRAND TERRACE  (AP) — A security guard died confronting a gunman firing at a crowd outside a Southern California roller rink where about 200 people, including many children, gathered for an all-night New Year’s Eve party, authorities and witnesses said Friday.

“He saved a bunch of kids and families, no doubt in my mind,” said Michael Marcoly, a driver who was sitting in his big-rig in the parking lot when the gunfire broke out at Cal Skate in the city of Grand Terrace, between Riverside and San Bernardino.

The guard, Richard Williamson, 48, of Riverside, was killed and two other men were injured, the San Bernardino County Sheriff’s Department said in a statement. Another security guard and a man were expected to survive.

A day after the shooting, detectives were asking for the public’s help in seeking suspects, and no details on a motive had been released.

Marcoly told KNBC-TV he thought the melee was part of the skating party before he realized the gunman was firing toward the crowd.

“At first, I thought it was just people celebrating the New Year, firing guns,” he said. “Then, when it hit my truck, it rocked my truck.”

The other victims were a 28-year-old and a 22-year-old, the sheriff’s statement said. One was treated at the scene, and the other was hospitalized. Their names have not been released.

The skating rink said in a statement that it’s working with authorities. Its website still had posted an advertisement for the event, billed as “All-Night Skate NYE 2015 Glow Party.”

“Our prayers are with the officer and who was involved and those who witnessed this tragic event,” the statement said.

Williamson was the owner of Big Will’s Security Services, the security firm that provided the guards for the party, the Riverside Press-Enterprise reported.