Three children among those killed in shooting at California birthday party

Police are investigating the shooting (Carlos Avila Gonzalez/AP)

US authorities have appealed for help in finding the person responsible for a shooting that left four people dead, three of them children, at a birthday party at a banquet hall in California.

Heather Brent, a spokesperson for the San Joaquin County sheriff’s office, said the children killed in Saturday’s shooting were aged eight, nine and 14. She said a 21-year-old also was killed in the attack during the party in the city of Stockton.