Police received a report at about 6:45 p.m. Tuesday of several suspects in the area of Sunset Avenue and West Avenue attacking another person with rocks and a baseball bat while yelling gang epiphets.
Officers responding to the area found an 11-year-old victim who had been struck in the head with a blunt object, police said.
The victim, believed to be associated with a criminal street gang, was taken to a local hospital where he was treated for a serious head injury, according to police.
The Santa Rosa Police Department's Gang Crimes Team identified one suspect as a 15-year-old boy who was a member of a rival gang. He was found during a traffic stop on Wednesday afternoon and arrested for the assault, police said.
Bertha Carreon-Somersall, an 18-year-old woman also in the vehicle, was brought in as well for interviews and later arrested for her alleged participation in the assault.
Both suspects face charges of assault with a deadly weapon and participation in a gang crime. Carreon-Somersall was booked into the Sonoma County Jail, while the 15-year-old boy was booked into the Sonoma County Juvenile Justice Center.
The Gang Crimes Team is continuing to investigate this incident for other suspects who may have been involved. Anyone with information about the case is asked to call police Detective Tom Isachsen at (707) 543-3670.