When police rushed to a rural house in Castlepoint in the Wairarapa early this morning, they believed only one person had been shot.
But by the time they arrived, the incident had become a double tragedy - a middle-aged couple both lay dead inside the house.
A person from the home on Masterton-Castlepoint had called 111 just after 5am to say there had been a gunshot and one person had been killed, Inspector Scott Miller, area commander for Wairarapa Police, told the Herald.
The armed offenders squad was deployed, but when they arrived to clear the house they found two people dead - a man in his 50s and a woman in her 40s.
Miller believed the deceased pair were a couple and had been in a relationship for some years. They had lived at the address for about a year, and neither they nor their property were known to police.
Police were also speaking with three other adults who had been at the address, all of them in their 20s. Those three had met police outside when they arrived.
Witness information suggested one firearm had been involved. It had been located and remained in the address, where police would be looking at it soon.
Miller could not confirm whether police were treating the incident as a murder and suspected suicide, saying only that a homicide investigation had been opened.
"At this point we have just done our scene examination. We have forensic experts who have come down from Auckland we also have our forensic team from Wellington and the Masterton police.
"This is a homicide investigation but the actual events of how it occurred, it'll take a day or two to put those pieces together.
"Talking to the residents inside the address and with our examination of the address we should know exactly what's happened within 24 hours."
Police had not had any previous dealings with the family or the property, "certainly not over the last 12 months or so."
"I think it is definitely a shock to the family and to neighbours," he said. "We'll be looking at all aspects of why this has occurred and what's happened."
Victim Support and police were offering support to those who had been inside the house from back at the Masterton Police station, as well as any extended whānau who needed support.
Police had knocking on doors within half a kilometre of the rural property. Only some people knew the occupants, but the general reaction from close neighbours was "disbelief and a bit of shock", Miller said.
He said the couple would likely not be named before tomorrow, in discussion with the family.
Police earlier said no one else was being sought in relation to the incident and there was no risk to the community.