Police remain committed to returning Yanfei Bao to her family, six months on from the Christchurch real estate agent's disappearance.
Bao went missing from the suburb of Hornby on 19 July.
Tingjun Cao has been charged with her kidnapping and murder.
The 52-year-old Chinese national pleaded not guilty to the charges in September last year and would face trial in October 2024.
Despite an extensive search over months centred on Lake Ellesmere and its surrounding suburbs, police were unable to find Bao's body.
Detective Inspector Nicola Reeves said it was something which haunted her.
She was committed to doing all she could to return Bao to her family.
"I think about it every day," Reeves told RNZ recently.
"The investigators are probably in the same boat, thinking about it every day. There's a huge sense of responsibility that we need to do that and we will continue doing everything that we can to find Yanfei and bring her back to her family."
A week after the 44-year-old disappeared, Reeves fronted media and told them the investigation was now a homicide.
Reeves had remained tight-lipped about what police believed had happened to Bao, but the police dive squad had combed the Halswell River and officers had also expressed interested in sightings of a metre-long Xcel brand spade.
"Everyone will remember we've spent quite a bit of time out in Halswell, Tai Tapu, towards Lake Ellesmere - we've had a huge focus out there," Reeves said.
"In terms of what I can say about what I think has happened to her, I won't make a comment on that."
Investigators still wanted to hear from members of the public who might have information leading to Bao's whereabouts or who might have seen a silver Mitsubishi 380 with the registration DPH101 in the days following Bao's disappearance.
While the Lake Ellesmere area was still a point of focus for police, they wanted to hear from people with sightings from further afield as well, Reeves said.
"It's still a really big area of interest to us, however, I'd just like to keep members of the public thinking about wider Christchurch," she said.
"We dont want to narrow it down. We want people to keep thinking about all suburbs. We know there's been some travel and some movement, so we just want to jog everyone's memory and ... keep people thinking wide about where they might have seen that vehicle.
"We've had an overwhelming response from the people of Christchurch and actually others from around the country and we're very grateful for that because it's really shaped a lot of the investigation and helped us uncover some very important things. But we are always looking for the smallest bit of information, even if people think it's irrelevant or silly or small, just tell us and let us make that decision as to whether it's relevant or not. We've got all the facts and they may just have that last little piece we are looking for.
"So certainly if somebody still thinks they've got something then by all means contact police and if I can just take that opportunity about the car - DPH101, and it's got a little yellow sticker on the back which has got a picture of a black kiwi bird in it so it's quite a distinctive car - if anybody's seen that, particularly on that Thursday the 20th of July, we'd be very interested in hearing from you."
Police wanted to bring closure to Bao's loved ones, but there was also the practicality of going to trial without knowing her whereabouts.
Reeves said police were preparing accordingly, though she would not divulge specifics.
"It changes things obviously. One of the things we are required to prove is that someone has been murdered. Now usually we do that because we have a body and we have injuries or a cause of death, so what we have to do in these circumstances is prove that by other means and it's what you'd call circumstantial evidence.
"We will present a number of facts to the court, to the jury, and part of that will be proving she has been murdered.
"I can't go into what they will be but it just changes how we go about proving that really important aspect, when we don't have a body."
Officers were not looking for anyone else in relation to Bao's disappearance.
In addition to hoping for new information to come forward, investigators were also regularly reviewing what they had already uncovered.
"Obviously any information will be really helpful and we will act on that as it comes in," Reeves said.
"But part of the investigation is we constantly review what we have; constantly reviewing if we have exhausted all of our inquiries; speaking with other investigators who may have experienced similar investigations as to what they've done; speaking to experts. Making sure we've done everything we should do."
"Certainly if anybody has new information, that's incredibly helpful, and we will act on that. But we'll continue to look at what we already know and take advice from elsewhere to make sure we have looked everywhere that makes sense for us to look."
RNZ
