A man charged over the fatal shooting of Sydney police officer Bill Crews has said he agreed to plead guilty to manslaughter because he was under "extreme stress", a court has heard.
Earlier this year, Philip Nguyen, 55, pleaded guilty to manslaughter and to wounding the trainee detective with intent to cause grievous bodily harm.
However, he now wants to change his pleas to not guilty, saying he was acting in self-defence at the time.
"I was under extreme stress when I agreed to the guilty plea," Nguyen told the NSW Supreme Court today.
Speaking through an interpreter, Nguyen said he sacked his barrister after she advised him to plead guilty to manslaughter.
"I did not commit that crime. I did not agree to that," Nguyen said.
Constable William Crews, a 25-year-old trainee detective, died after he was shot during a drug search in a basement carpark at Bankstown in Sydney's southwest on September 8, 2010.
Nguyen did not fire the fatal shot but he was charged with manslaughter on the grounds of "excessive self-defence".
The crown has alleged Nguyen, a drug dealer, produced a firearm during the raid and fired it, hitting Const Crews in the arm.
The constable fired three shots in return before a fellow detective fired once, accidentally shooting the constable in the neck.
Nguyen gave evidence he had purchased a gun to protect himself after being robbed and assaulted.
He said he didn't know the men who entered his garage on the day of the incident were police.
"When two to three people are pointing guns at me, I had to draw my gun out for self defence," he said, adding, "I would say police fired first".
Crown prosecutor Mark Tedeschi, QC, said there was evidence that Nguyen fired the first shot and that Nguyen's second barrister had told him that.
"He (also) explained to you a jury would not have much sympathy for you because you were a drug dealer and you had bought a gun to protect yourself," Mr Tedeschi said.
"It's possible he said so," Nguyen replied.
Earlier, the court heard Nguyen had a stroke two weeks ago, could not communicate properly and was having memory difficulties.
However, his solicitor, Ho Ledinh, said he was well enough to take the stand.
The hearing continues.
