Christchurch police say they have made significant findings at a Hornby property where a missing real estate agent was last seen.
Yanfei Bao, 44, disappeared 10 days ago, and the investigation has since been upgraded to a homicide case.
A 52-year-old man has been arrested and has appeared in court charged with kidnapping.
Police have launched an extensive air, land and ground search for Bao involving more than 40 people and covering several areas of Christchurch.
Much of the work today has again focused on the Halswell River area around Lake Ellesmere at Greenpark searching for Bao and other items of interest.
Detective Inspector Nicola Reeves, who is leading the inquiry, told Checkpoint nothing had been found during today's searches.
The Trevor Street house in Hornby where Bao was last seen on 19 July remained one of the keys to the case, she said.
She refused to say if police believed Bao was killed there but said the house remained significant for the investigation.
"I'm not going to go into specifics of what took place there or what it is that we have found there other than to say it is certainly one of the contributing factors that has seen it change from a missing person to a homicide investigation."
She confirmed an open home was held at the property (which is for sale) days after police had been told Bao was missing.
Police visited it in the first few days but it was still a missing person investigation at the time and was not upgraded to a homicide inquiry until Wednesday.
It was one of several properties the police visited looking for Bao.
"It's an evolution I suppose is the way to put it but we seized the address under warrant on Sunday."
Asked if it complicated the inquiry that members of the public had gone through it in the meantime, Reeves said police often had to consider with locations of interest what they looked like at the time (of a crime) and what had happened since then. ESR staff helped with this, she said.
The police's forensic inquiries at the Trevor Street property have been completed.
Renewed appeal for sighting of grey Mitsubishi
Police were still interested in sightings of the two vehicles and were still trying to confirm how Bao's vehicle was moved from Trevor Street in Hornby to Iroquois Place in Wigram.
She also appealed for sightings of the grey Mitsubishi vehicle with the kiwi sticker on its boot on Thursday 20 July and a registration number of DPH101.
Asked if there was evidence Bao had been in the vehicle, she refused to say. It had been forensically examined and results were still coming through.
Reeves also refused to discuss anything about the arrested man including a report that he had only been in New Zealand for a few months.
Meanwhile, the air, ground and land search was being constantly assessed.
"People in Christchurch will remember that last weekend that area was quite flooded so we have been limited in when we can get out there ...The area is still under quite a bit of water. So it will be an assessment of results and watching that water level and when we can get into other places that we think we want to take a look at."