Police say they are searching a landfill in Porirua following the violent death of an elderly woman in the Wellington suburb of Khandallah last month.
Helen Gregory, 79, was found dead in her home on 24 January and police said she died as the result of a violent act.
On Friday morning, police began searching the landfill for things they believe were discarded by a person of interest several hours after her death.
Detective Senior Sergeant Tim Leitch said the investigation was continuing to piece together the events leading up to, and following, Gregory's death.
Specialist search teams were focused on a specific area of the landfill and were looking for "items that could significantly advance the homicide investigation".
"The investigation has uncovered significant evidence enabling the team to develop a clear understanding of the circumstances surrounding the death, and I am confident of a successful outcome," he said.
He urged anyone with information to contact police.
The city council said people should expect severe odours as police dug up the landfill.
Porirua's mayor Anita Baker said council staff were assisting with the search.
"I just hope that they find what they're looking for and the smell's worth it for them."
Meanwhile, on her obituary page Gregory has been described as a warm, dignified, kind person who loved wearing bright colours and had an infectious laugh.
Those paying tribute said she loved her garden, family, and spent time doing charity work.
She was also involved in the church.
A memorial service will be held for her next Friday.