Police are looking for four men in their 20s after a 30-year-old woman was killed at her home in Upper Hutt.
Lois Rita Tolley was found dead at the flat on Ward St shortly after midnight yesterday morning.
Detective Senior Sergeant Warwick McKee said this afternoon they were still looking for a group of young men seen at the property about that time.
They were also looking for a knife as well as a firearm now believed to have been used in the attack, he said.
"Just prior to the incident, at around midnight, four males were seen jogging south along Wilford St towards Ward St," he said.
"One of the males was carrying a long rectangular object ... They are described as all about 182cm tall and wearing dark clothing with hooded tops."
The men were seen leaving the property after Ms Tolley was killed, and one of them was described as "visibly distressed", Mr McKee said.
He urged the men, and anyone else who might have information, to contact them.
"I would like to appeal to these people to come forward to police: take the brave step, front-foot this and give an account of what happened at that address on Saturday morning."
'Incredibly difficult time'
Police had contacted Ms Tolley's family, who were spread throughout Australasia, and her mother had travelled to New Zealand from Australia.
The victim was the youngest of four children and part of a large extended family, Mr McKee said.
"This is an incredibly sad and stressful time for the family, who police are supporting through an incredibly difficult time so close to Christmas.
"The family are devastated by this act of violence that has taken their much-loved Lois from them."
He said earlier today that about 20 investigators were trying to find out what happened.
A post-mortem was carried out earlier today. Forensic investigators were still at the scene.