Schools were on lockdown or closed in the Silicon
Valley city of Cupertino and nearby Los Gatos as police searched for the suspect, Shareef Allman, 47.
Two people died at the scene and a third died several hours later at a local hospital.
Two brothers, who were also union leaders at the quarry, were among the victims, NBC affiliate KNTV reported, quoting a brother of the men. One of the men died and the other was wounded, KNTV reported.