Six young people were injured when a shootout broke out at a sweet sixteen party in Antioch on Saturday night, police said.
Police responded to reports of a shooting at a residence in the 5000 block of Wilmont Court shortly after 10:30 p.m.
The calls indicated that there were 70 to 80 people at the residence and many had run away.
Police arrived to find a sweet sixteen party thrown at the residence had ended in violence when an argument broke out between some of the 30 or 40 partygoers in the house's garage.
Police in Antioch believe three or four male partygoers opened fire when two groups began arguing, said police Lt. Scott Willerford. Violence is not common in the neighborhood in Antioch, which is about 38 miles northeast of San Francisco.
"Weapons were brandished and numerous shots were fired from multiple guns,'' Willerford said.
Among the injured were a 13-year old Antioch resident, a 21-year-old Antioch resident, an 18 year-old Antioch resident, two 16-year old Antioch residents, and an 18-year-old Brentwood resident.
All six were transported to local hospitals, some by ambulance and others by helicopter. Three of the wounded have been released from hospitals, but the 13-year-old, an 18-year-old and the woman remained in serious but stable condition, police said. Their names have not been released.
Police are looking for three or four suspects described as "young men,'' but acknowledge they haven't been able to obtain more detailed descriptions. Willerford said callers reporting the shooting had said between 70 and 80 people were at the party, but many of them ran away when the gunfire broke out.
Authorities said the party was being thrown by the girl's parents.