A senior police officer who oversaw a 50-hour siege in Napier in which an officer was killed told a Coroner's Court on Tuesday the gunman had been a drug dealer for a decade.
Jan Molenaar shot dead Senior Constable Len Snee during the siege in the suburb of Hospital Hill in May last year.
Molenaar critically wounded two other officers and a civilian, then barricaded himself in his house where he shot himself with a revolver a day later.
Coroner David Crerar is holding an inquest in Napier into the deaths of Senior Constable Snee, 53, and Molenaar, 51.
Detective Superintendent Rod Drew told the court Molenaar also tried to kill at least a dozen other people.
He said a thorough investigation into the events questioned why Molenaar reacted so violently to police wanting to search his house for drugs.
Detective Superintendent Drew said Molenaar had been a drug dealer for at least 10 years, and had no other source of income.
He had told drug associates that if the police caught him, he would not be taken and would not go to prison.
Not on file
Detective Superintendent Drew said there was nothing on Molenaar's police file to cause alarm to the three senior constables who went to search his house for drugs on 7 May.
But he said it later transpired that drug associates of Molenaar knew of his mental state and that he had a large store of illegal weapons.
Superintendent Drew said it was unfortunate one of them did not tell police.
He said when Molenaar returned home, he grabbed a high-powered rifle and coolly shot Senior Constable Snee at close range before shooting him again as he lay on the ground.
He said the gunman then turned his rifle on Senior Constables Grant Diver and Bruce Miller, and a member of the public, Len Holmwood.
He told the inquest if Molenaar had not shot himself, he would be facing 18 charges of attempted murder.
Mr Crerar, the Dunedin coroner, is conducting the inquest, following a decision by the Chief Coroner. It is set down for three days and will hear from a total of 13 witnesses, including eight officers and the gunman's former partner.
