The search for a missing Christchurch real estate agent remains focused on waterways south of Christchurch, but police are still trying to track exactly where the car of the man charged with her kidnapping went the day after Yanfei Bao disappeared.
The homicide investigation has entered its third week of searching for Bao, who went missing while conducting business as a real estate agent.
A dive squad has been searching the Halswell River and looking again in waterways around Greenpark and Lake Ellesmere with land searches too.
Detective Inspector Nicola Reeves told Checkpoint more than 200 tips off from the public and other factors were leading them to the current search area.
"We have a look at what we have or have not found and assess that for any relevant - I won't be talking about any of those items or whether we have found anything. But it's always subject to an assessment to make sure we've covered the right place and perhaps where we need to be going next."
Reeves said she could not detail what it exactly was that was pointing them to search in those areas, and she could not rule out further charges.
"We have got a huge investigation team working on this and we have also had enormous support from members of the public. As a result of that and the work that's been going on we know that this serves an area of interest for us, that's what our inquiries have pointed us to so that is an area that we really need to cover off, and that's a process we're undertaking at the moment.
"There's still a lot to get through and a lot of inquiries that need to be exhausted, but that's exactly what we will do.
"We will search wherever this investigation takes us and when we're satisfied that we are in a position to either lay further charges or not then we'll make that known."
She was "incredibly hopeful" of finding Bao's body.
"We have got the very best people with the very best expertise, who are working the ground, completing those searches for us.
Reeves was of the understanding that Bao's China-based family members were still making arrangements to come to New Zealand.
"We had thought they might have got here earlier but there's travel arrangements and visas that need to be arranged so that's underway and they will get here as soon as they can."
A forensic examination carried out at a Trevor Street house which was on the market with the agency Bao worked for has now been returned to its owners.
Reeves said investigators remain interested in any sighting of a silver Mitsubishi sedan with the registration DPH101, particularly on 20 July, which has a yellow diamond-shaped sticker with a black kiwi bird on it.
"We know that this investigation has taken us in to a few different areas of Christchurch so I'm not ruling out where that vehicle may or may not have been. It's a general request for the greater Christchurch area."
Information can be given to police via 105, either by calling or going online using 'Update Report', using reference number 230720/5911.