The man accused of slaying three managers of a Santa Clara semiconductor firm in 2008 has testified he wanted to commit suicide in front of the managers but his gun went off as one of them thrust a chair at him.

Jing Hua Wu, a former engineer for SiPort, Inc., said while discussing his firing with the managers on Nov. 14, 2008, he produced a 9mm pistol, declared he would shoot himself and then turned his attention to Brian Pugh, the firm's vice president of operations.

"He pushed the chair toward me so I had to protect myself," Wu testified Wednesday while holding his hands up in a defensive position.

"At that point I felt that my gun went off," he said. "I think the (gunshot) hit the lower half of him."

Wu, 51, has pleaded not guilty to three counts of murder in the shooting deaths of Pugh, SiPort CEO Sid Agrawal, 56, and human resources manager Marilyn Lewis, 67, inside Agrawal's office.

The charges also include special-circumstance allegations sought by prosecutors and if he is convicted, Wu could be eligible for the death penalty.

Deputy District Attorney Tim McInerny claims that Wu allegedly shot Pugh in the top of the head, his chest and buttocks, Agrawal once in the side of the head and once in the neck and Lewis once in the side of her head.

Wu, a native of China who speaks English, took the stand for the second straight day Wednesday morning, speaking in Mandarin Chinese with an interpreter sitting beside him translating.

His defense attorney Tony Serra told the jury in January he would argue that the political persecution and brutality Wu faced as a boy growing up during the Cultural Revolution in Communist China in the 1960s and Wu's mental illness contributed to the shootings.

Serra asked jurors to consider Wu's "mental diseases and defects" at the time of the homicides and convict him of the less-serious charge of manslaughter.