A secret police witness gave dramatic evidence on Monday about the night an officer was killed in a covert police operation.
A hearing at the Manukau District Court will decide whether John Ward Skinner and Ian Lindsay Clegg are to stand trial for the murder of Sergeant Don Wilkinson and the attempted murder of his colleague.
The court was cleared to conceal the identity of an officer who was providing cover as Sergeant Wilkinson and his colleague installed a tracking device at John Skinner's house.
He says they were probably betrayed by a security light going on.
The witness said shortly after the light went on, several people emerged from the house, shouting aggressive challenges at the two officers, who he assumed had escaped.
He said one of the men then pointed a gun at him, but thought he was a man out for a walk and backed down.
The witness told the court that shortly afterwards, he heard the two officers had been shot.
He said most officers were issued with stab-proof vests but many - including Don Wilkinson - chose not to wear them.
The senior officer said he now insists the the vests are worn.
The defence lawyers say the officers could have looked like burglars, and asked the secret witness why he did not defuse the situation by declaring himself a policeman.
The witness said his instinct was to not jeopardise the operation.