The killings took place in two different places in Bakersfield city on Wednesday night and Sheriff Donny Youngblood of the Kern County said the incident was not a random mass shooting, reports Efe news.
"This is highly unusual to have six people shot and dead in one incident," The Bakersfield Californian daily quoted Youngblood as saying. The sheriff said that the incident began at a trucking company where the suspect arrived with his wife.
According to the reported sequence of events, the suspect confronted a man at the place, and shot him dead and then shot his wife. He then followed another man and killed him at the same place, before heading to a residence where he confronted and killed two more men.
He afterwards hijacked a vehicle with a woman and her son, but they managed to escape. Finally when the police intercepted the vehicle and confronted the killer, the suspect shot himself. Bakersfield is some 145 km north of Los Angeles.