A man convicted of killing a turbaned, bearded Sikh (search) he mistook for an Arab suffered from acute stress and a brief psychosis triggered by the Sept. 11 terror attacks, a psychiatrist said Tuesday.

The testimony came as jurors considered whether to sentence Frank Silva Roque (searchto death for fatally shooting Balbir Singh Sodhi in front of Sodhi's gas station on Sept. 15, 2001.

After the killing Roque shot at another gas station, where the clerk was of Lebanese descent, and shot at the home of an Afghan family. No one else was hurt.

Prosecutors say Roque, 44, targeted Sodhi because he believed the Indian immigrant was Middle Eastern.

"Had Sept. 11 not occurred, this horrific event would not have occurred," said Dr. Jack Potts, a court-appointed psychiatrist.

Potts' testimony was a turnabout. During the trial, Potts testified for prosecutors, saying he believed the notion that Roque was mentally ill to be "clearly arguable."

But he now says he has done additional research on post-traumatic stress disorder (searchprompted by the Sept. 11 attacks and believes Roque's rage fits that pattern.

Roque's attorney contends his client was insane at the time of the shooting -- a paranoid schizophrenic -- and that the crime was not racially motivated.

Jurors also heard from Sodhi's family. His brother and son said the gas station owner was known to give children free candy and customers short on change a break.

Lakhwinder "Rana" Singh Sodhi said his brother called him to ask for a favor 30 minutes before the shooting.

"He asked 'Rana, could you bring me an American flag. I can't find one in my area,"' Rana Sodhi said.

Jurors were expected to begin deliberating late Wednesday afternoon.