Police have a new lead in the execution-style killing of Lois Tolley.

Today marks two months since the 30-year-old was stabbed and shot at point-blank range in her Ward St, Upper Hutt, home.

Detective Senior Sergeant Glenn Barnett said police were looking for the owner of a silver vehicle seen in the area at the time of the murder - a different car to the three police have spoken about.

Last month, police appealed for sightings of three vehicles, which were blue, white and silver.

The owners of the blue and silver cars have been spoken to.

Barnett said another silver vehicle seen in the area at the time was not included in the original three.

"We are just trying to get further with this other silver vehicle, possibly a BMW with blacked out or darkened tyres that we believe was close to Lois' house."

Police still believe four people were involved, but don't know where they are.

"Those four people, with something like this, will be talking to other people, they'll be talking to family members and loved ones, there'll be people out there who have information on this.

"The team is confident that we're definitely heading in the right direction and there will be results leading to the arrests of the people responsible for this," he said.

Anyone with information is being urged to come forward.