Senior Constable Len Snee died from three gunshot wounds and his death would have been instantaneous, police say.
Detective Superintendent Rod Drew said a post mortem held yesterday revealed Mr Snee had been shot in the arm and on the upper torso and lower torso.
"Neither shot to the torso was survivable, even in the event of immediate medical attention. Bullet fragments from a military style round, probably a .223 calibre, were found," Mr Drew said.
A team of around 60 investigators from Hawke's Bay, Gisborne, Wellington, Bay of Plenty and Central Districts are now working their way through four separate investigations.
• The murder of Senior Constable Len Snee • The attempted murder of Senior Constables Bruce Miller and Grant Diver • The attempted murder of Len Holmwood • The attempted murders of neighbours and passers-by and other emergency services workers
There are also ESR scientists and forensic investigators at the scene today who are sifting through an array of evidence. Bomb experts are also still at the scene.
Mr Drew said while the explosive devices at the house had been disarmed by the bomb squad, there was the possibility that some were still undiscovered in the house. More intensive searches would be conducted today.
The body of Jan Molenaar is expected to be removed later this afternoon. His injuries will be confirmed during a post mortem to be held tomorrow.
"Our investigators today will be interviewing a range of people, including police tactical staff who were involved in Thursday's events.
"There were several acts of bravery by police and other emergency staff at the scene and we have yet to speak to them. But I can say there were some heroic acts of bravery that took place that day, the details of which will come out over the next few days."
Mr Drew said police were slowly building up a picture of events that took place on Thursday. More information would be revealed in the coming days as detectives interviewed a large number of witnesses and others who were involved in the event.
"Not only did Molenaar open fire without warning or provocation at the three unarmed police officers, but he also ran down the road and fired shots at them as they tried to reach cover. It was then that Len Holmwood showed immense bravery in trying to disarm Molenaar. He grappled with the gunman and was shot in the left thigh. He was able to drag himself a short way down the road where he took cover behind a wall until he was rescued by AOS members."
Police fired two shots at Molenaar's house on Thursday. Although the investigation into that has not been finalised, police believe the officers complied with the law and the shots were fired in accordance with Police regulations to defend the lives of police staff and members of the public.
Mr Drew said at least 18 weapons have been found in Molenaar's house so far, mostly high-powered military-style and shotguns.
"There is the possibility that there may be more, and our searches over the next few days may confirm that."
Police will also be speaking to residents in the area today and intensive searches of the house will continue.
Senior Constable Bruce Miller and Mr Holmwood remain in a critical condition in Hawke's Bay Hospital, while Senior Constable Diver is stable, but improving.
NOTE; We are currently working on getting some pix of the weapons. They will be emailed out when available.