In a tragic incident in Stockton, California, four individuals, including three children, lost their lives in a shooting at a child’s birthday celebration on Saturday evening.

According to a statement from the San Joaquin County Sheriff’s Office, 11 people were injured during the attack. The victims who died were aged 8, 9, 14, and 21.

Stockton Vice Mayor Jason Lee shared on Facebook that the violence erupted during what was meant to be a joyous occasion—a child’s birthday party.

As reported by The Sacramento Bee, the shooting occurred shortly before 6 p.m. at the Monkey Space, a venue that previously served as a children’s theater company.

Authorities have yet to apprehend any suspects. However, Mayor Christina Fugazi described the event to KTXL as an act of “domestic terrorism” and “gang violence,” though she did not provide evidence to substantiate these claims, and law enforcement has not confirmed this as their line of investigation.

She also said that a “bounty” on the suspect is $25,000.

Police say they aren’t sure if they are looking for one suspect or multiple suspects, but that “detectives are actively working on suspect descriptions and moving toward identifying and locating the individuals responsible for this horrific act.”

They have asked for information and/or video footage from the event to help them find those responsible.

This story is developing. Check back for more information.