Police say the "routine operation" which left an undercover police sergeant dead in Mangere, south Auckland, today was not considered a high risk.
Sergeant Don Wilkinson, 46, died instantly from a single gunshot wound to the chest during a covert drug operation. His 44-year-old colleague, also a sergeant, was shot several times and assaulted. He was due to have surgery in Middlemore Hospital today but his injuries were not thought to be life-threatening.
Two men appeared in the Manukau District Court today after the shootings.
One, 33, was charged with murdering Mr Wilkinson and the other, 37, was charged with assaulting him. Both were remanded in custody without plea until later this month.
Both also were given name suppression. The name of the injured policeman was also suppressed.
The two police officers were installing a tracking device on a car at a house in Hain Avenue, Mangere, about 1.44am when they were disturbed by the two occupants of the house.
Both police officers, who were unarmed, fled on foot but were chased by the two men in a car for a short distance when both were shot.
As they ran, they called for help on a police radio to other members of their covert police team a block away.
The other police were armed and took only seconds to reach the two policemen, but they were too late to stop the shooting.
Police said today they had targeted the house and the occupants, but the assessment carried out before the operation early in the morning did not rate the risk as high.
Superintendent Ted Cox said they were not aware of the firearm in the house, suspected of being a clandestine drug laboratory.
Had police known the two men were armed they would have approached the operation differently.
"Regrettably events unfolded too quickly for other (armed) officers to be able to respond and intervene and we now have this tragedy," Mr Cox said today at a media conference.
He was asked if police got it wrong when their intelligence assessed the operation as low risk.
"Hindsight is a great thing because it has happened.
"The reality is that all those procedures and checks were carried out and there was nothing to heighten the awareness.
"We are very conscious obviously of the link between clan labs, methamphetamine and firearms. It is part of the daily picture unfortunately."
Mr Cox was also asked how the operation would have been handled had police known there was a firearm in the house.
"If we knew there were weapons in the house we would have approached it entirely differently,' Mr Cox said.
The two police men were not armed, but one was wearing stab-resistant body armour.
"Neither was wearing ballistic armour, which is the heavy calibre type stuff.
"Basically we would not have been in that situation if there was such a threat to require ballistic armour," Mr Cox said.
The two men were part of a seven person team and were installing the tracking device on the car when they were disturbed .
The police fled on foot, probably without declaring themselves to be police because of the protocol undercover officers followed, Mr Cox said.
As they were chased by the two men in a car they alerted their colleagues on a police radio. They also probably knew they were being chased by armed men, Mr Cox said.
After 75 metres they were caught and shot, but by then the back up squad members were on their way.
They arrived seconds later to find Don Wilkinson dead on the road and the other sergeant badly wounded.
They protected their colleagues as more armed police arrived and cordoned off the house where the alleged offenders were inside.
"We then went into a normal cordon type of role, secured the premises to make sure the offenders couldn't leave and there was no ongoing risk to staff and danger to the public," Mr Cox said.
Mr Wilkinson's body lay on the road for several hours as police questioned neighbours and the two men they later charged with his murder and assault.
Police also found four children in the house, ranging in age from 11 months to 15 years. They were being cared for by family members.
* Undercover police setting tracking device at 1.44am
* Offenders disturb officers who run off
* Offenders follow in a car and catch up the officers
* Sgt Don Wilkinson is shot once in the upper body and dies
* A 44-year-old officer is repeatedly shot and assaulted. He survives
* Police question two men
* One man is charged with murder, another with assault
Do you know Sgt Wilkinson or his colleague?