Officers responded to a call of the stabbing in the 100 block of W. Bluebell Avenue. By the time they arrived, one 55-year-old man, one 24-year-old man, a 66-year-old-woman and a 48-year-old woman were wounded, police said on Twitter.
Gino Fuentes, 20, was arrested by Anaheim police for the stabbings.
A man who lived across the street from the residence where the attack took place said he saw one of the female victims stumble outside while he was working in his yard. "I saw her shirt full of blood and her gushing out blood from her neck," Manuel Gonzalez said.
Gonzalez saw Fuentes, who was holding a knife, fighting with another bloodied person. Gonzalez grabbed a crowbar and a bat and sprang into action.
"He already had stabbed four people, so I said, 'These people's life is in danger as well as mine and everybody that's around here,'" Gonzalez said. He grabbed the bat and struck Fuentes in the ribs four or five times, causing the suspect drop the knife and run back into the house.
When Fuentes emerged from the residence for a second time, he had a larger knife in hand.
Gonzalez immediately gave chase. "I chased him with the crowbar and I hit him one more time in the back," Gonzalez said. Gonzalez only stopped running after the suspect when his parents urged him to stay put because the police were on their way.
The four victims remain in critical but stable condition.
Fuentes was arrested by police about a mile from the scene, according to Anaheim PD. Fuentes is charged with four counts of attempted murder and one count of elder abuse. His bail has been set at $500,000.