Police say an Upper Hutt woman killed in her own home was shot "execution style" at point-blank range, in one of the worst cases they've seen in recent memory.
A homicide investigation is underway after 30-year-old Lois Tolley was found dead in her Upper Hutt flat earlier this month.
Police are still on the hunt for four young men seen walking towards Ms Tolley's house on the night of her death, and then leaving the property a short time later.
Detective Senior Sergeant Glenn Barnett says Ms Tolley was "viciously stabbed and shot at close range" in an "execution-type killing".
Det Snr Sgt Barnett said he believes the information and evidence police have gathered will identify the killers.
He is calling for those who saw what happened, but were not the main players, to contact police.
"The door is open for those who were here on the night, but not a main player, to come forward in confidence to us," he said.
A team of 20 to 30 police staff continue to work towards tracking down the killers.
They are working through CCTV footage, forensic material and evidence from the scene, and speaking to a large number of witnesses and family members.
The murder weapons used include a knife and gun, which are still yet to be located.