Los Angeles-area woman and dog fatally stabbed, suspect knocked out with rock

A Los Angeles-area grandmother and her dog were stabbed to death Thursday by an attacker who was knocked out by a bystander who used a rock to knock him out, authorities said. 

"The call indicated a woman was screaming and later updated indicating a woman was being stabbed," the department said.  Deputies found the woman with multiple stab wounds and she was pronounced dead at the scene, authorities said. The dog was lying next to her and was also pronounced dead.  Witnesses said the alleged attacker kept yelling that he was going to kill someone. He first went after a man in his 30s who ran away from him, authorities said. The suspect then turned his attention to the woman walking her dog.