Napier gunman Jan Molenaar died from a single, self-inflicted gunshot to the head, a post-mortem examination has found.

There was no other bullet wound or injury to his body, Detective Superintendent Rod Drew said yesterday.

Police fired two shots at the 51-year-old during a siege that began last Thursday morning at Molenaar's Chaucer Rd house on Napier Hill.

Police reports before the autopsy result said that Molenaar had told them he had been hit in the exchange of fire.

His body was found by armed offenders squad members in the house on Saturday morning.

"The overall picture of this dreadful event is becoming clear," Mr Drew said.

Senior Constable Len Snee was fatally shot by Molenaar last Thursday morning.

Senior Constables Bruce Miller and Grant Diver were critically injured, as was civilian Lenny Holmwood, all by gunshots fired by Molenaar.

Mr Drew said there was evidence to suggest Molenaar had attempted to shoot 18 other people dead during the incident.

There were shots fired by the gunman at police, people attempting to rescue those injured and people in nearby houses.

"It really is extraordinarily lucky that nobody else was injured or killed."

Molenaar was found wearing a sweat top which had a protective fabric sewn on to the front and back.

He was also wearing a leather vest and on the back was a homemade garment, akin to a motocross rider's protective shell, which also had the same material sewn into it, Mr Drew said.

"There was also a metal sheet that had been fashioned, it was made to hang over the shoulders and came down like a bib at the front, which no doubt was intended as a bullet-proof garment."

The protective measures were "almost certainly" manufactured by Molenaar long before last week's incident, Mr Drew said.

The two shots fired by police drove Molenaar back into his house and from then on the gunman was unable to take clear aim at anyone outside, Mr Drew said.

The rest of his shots were fired through windows, walls and the blinds. "Undoubtedly, even though it was still a very dangerous situation, it was less dangerous than if he was taking aimed shots from outside the house," Mr Drew said.

All firearms found by police in Molenaar's home - nine in his bedroom and nine elsewhere - were loaded with their safety catches off.

Police, who have almost finished a canvas of the area have discovered bullets up to 400m from the house. The scene examination of the house was not due to be completed for some time.

Police believed Molenaar suspected they had been casing out his home a week before the shooting, but that was not the case, Mr Drew said. "That was a figment of something happening in his mind - it was not an actuality."

The investigation had been very difficult for the officers involved, he added.

"Many of us knew Lenny [Snee] well, some of us knew him very well.

"I feel very proud of them all because they've shown real grit in getting on with the job." Mr Diver's condition had improved. Mr Miller was still in the intensive care unit of Hawkes Bay Hospital, where his condition was stable but improving.

Mr Holmwood was also improving, and was due to have a further operation yesterday to remove shrapnel.