An expelled Korean adult student shot dead seven people at a Californian university after being teased over his poor English skills.
One L Goh opened fire at random when he found his intended target, a woman administrator, was not in the building, police said.
He at first asked people to line up, Oakland Police Chief Howard Jordan said.
"Not everyone was co-operative, and that's when he began shooting," Mr Jordan said. The dead included six students and a secretary.
The 43-year-old had been expelled from Oikos University, possibly for behavioural problems, and was upset with school administrators and with several students because of the way he had been treated when enrolled two months ago.
"They disrespected him, laughed at him. They made fun of his lack of English speaking skills. It made him feel isolated compared to the other students," Mr Jordan said.
"We've learned that this was a very chaotic, calculated and determined gentleman that came there with a very specific intent to kill people, and that's what his motive was and that's what he carried out," He said.
Five people died at the scene and another two on hospital. Three wounded victims were in stable condition, and at least one person had been released from the hospital.
The private school serves the Korean community with courses from theology to Asian medicine. "Pastor Jong Kim, who founded the school about 10 years ago said he heard about 30 rapid-fire gunshots in the building and stayed in his office.
Goh was held at a supermarket about an hour after the shooting. A security guard approached him because he was acting suspiciously. He told the guard that he needed to talk to police because he shot people