Wellington, Sept 3 NZPA - The presence of an extra police officer at the search of Jan Molenaar's home could have saved the life of Senior Constable Len Snee, coroner David Crerar said today.

Molenaar, 51, shot dead Mr Snee and wounded two other officers, Senior Constables Grant Diver and Bruce Miller, after they attempted to carry out a cannabis search at Molenaar's Napier property on May 7 last year.

Civilian Len Holmwood, who had been visiting Molenaar when the officers went to carry out the search, tried to intervene and was also shot and injured.

Molenaar later shot himself dead, ending a three-day siege.

Mr Crerar released his findings into both deaths today following an inquest from March 30 to April 1.

Among his findings, Mr Crerar found that if another officer had been present at the search then Mr Snee might not have been killed.

"Although I agree that more police at the time of the execution of the search warrant may have had the outcome of more shooting victims, it is clear that the presence of an extra police officer may have avoided the tragic outcome," Mr Crerar said.

"Constable Snee could not adequately control Lenny Holmwood, Delwyn Keefe and Jan Molenaar and it would have been better if a police constable had accompanied Jan Molenaar when he left the room."

While Mr Crerar agreed with police that Molenaar's response to a police search was totally disproportionate to the seriousness of the incident, he said police had insufficient intelligence about Molenaar.

Mr Crerar also questioned the community's inaction in coming forward with information about his state of mind.

"Intelligence relies on public support," Mr Crerar said.

"A number of persons, including some who gave evidence to the inquest hearing, knew that Jan Molenaar would be upset by the entry of police on to his property.

"Each and every person who knew, or considered it possible, that Jan Molenaar would react in a violent manner or in a way the police may have considered to be unpredictable, owes a responsibility to report their concerns to police.

"There is a matter of enduring regret that this did not happen."

Among Mr Crerar's recommendations was a review of the Arms Act, which he said was currently only complied with by honest people.

He also made several recommendations for changes to police search procedures, which police today said had already been addressed.

The report described how Molenaar's partner, Delwyn Keefe, tried to stop Molenaar when she saw that he had a rifle aimed at the three police constables.

"Delwyn Keefe said that she ran towards Jan Molenaar with her arms in the air and told Jan Molenaar to put the gun down," the report said.

"She then turned her back to Jan Molenaar and said to the constables: 'Get out, because you don't know him like I do'."

Keefe provided the court with two notes left for her by Molenaar which read: "I was bad. I paid for my crime. I let everyone down, I know. JM" and "I love you Del, you are so loyal, faithful, good person. I did my best to make you happy, love JaniMo forever".

Keefe told the court she believed the notes were indicative of Molenaar's remorse.

Keefe was last year sentenced to two years and three months' jail after being convicted on cannabis charges.

The coroner found that Mr Snee died as a result of wounds from gunshots fired by Molenaar and that Molenaar died from a self-inflicted bullet wound to the head.