Several people were killed in the northern coastal city of Half Moon Bay on Monday (January 23), about 30 miles south of San Francisco.
In a late news briefing, Sheriff Christina Corpus named Monday's suspect as 67-year-old resident Chunli Zhao.
She said deputies had found him in his vehicle in the parking lot of the sheriff's substation.
Corpus said officers responding to a call found at least seven people shot dead in two locations near each other in Half Moon Bay.
She added that police did not yet know the motive for the killings.
In the earlier shooting, eleven people were killed in southern California, in the city of Monterey Park in Los Angeles County.
