Authorities in California appealed to the public for tips, cellphone video, witness accounts and even rumors as they searched Sunday for a suspect in the killing of three children and an adult during a mass shooting at a child’s birthday party.

Someone opened fire at a banquet hall in Stockton where 100 people or more had gathered on Saturday, San Joaquin County Sheriff Patrick Withrow told reporters. He said detectives believe the gunfire continued outside and there may have been multiple shooters.

Withrow said the deceased were ages 8, 9, 14 and 21. Eleven people were also wounded, with at least one in critical condition, he said. No one was in custody by Sunday evening, and the sheriff urged anyone with information to contact his office.

“This is a time for our community to show that we will not put up with this type of behavior, when people will just walk in and kill children,” Withrow said during a Sunday media briefing. “And so if you know anything about this, you have to come forward and tell us what you know. If not, you just become complacent and think this is acceptable behavior.”

Sheriff’s spokesperson Heather Brent said earlier that investigators believe it was a “targeted incident.” Officials did not elaborate on why authorities believe it was intentional or who might have been targeted.

Faith leaders held a Sunday afternoon vigil to honor the dead and pray for the wounded.

The shooting occurred just before 6 p.m. Saturday inside the hall, which shares a parking lot with other businesses in the city of 320,000 residents about 80 miles (130 kilometres) east of San Francisco.

“This was a birthday party for a young child, and the fact that this happened is absolutely heartbreaking,” Brent told reporters. She said investigators would welcome any information, “even rumors.”

District Attorney Ron Freitas urged the shooter to “turn yourself in immediately.”

Hours after the shooting, the Stockton Police Department arrested five people, including a juvenile, on weapons and gang-related charges. There was no indication that the arrests were connected to the killings at the banquet hall, the sheriff said.

Mayor Christina Fugazi told reporters that the 8-year-old victim attended a local school and had a parent who worked for the Stockton Unified School District. The mayor said counselors would be available this week at city schools.

Community leaders expressed anguish over the loss of victims so young.

They should be writing their Christmas lists right now. Their parents should be out shopping for them for Christmas. And to think that their lives are over. I can’t even begin to imagine what these families are going through. Breaks my heart,” Fugazi said on Sunday.

In 2024, Stockton had many more homicides -- 54 -- than other California cities of similar size, but the rate was down through October of this year, according to city data.

Fugazi on Saturday recalled a shooting several years ago in which “seven people were gunned down” in the city.

Withrow said he cut his family’s Thanksgiving celebration short and drove more than eight hours from Oregon to the shooting scene.

“I put down my grandbabies, to come hunt down these animals who took somebody else’s babies away from them,” the sheriff said.