Police are now focusing on locating the person who picked up Christchurch woman Ngatai (Mellory) Manning at 10.35pm on Thurday evening.
"It was a reasonably warm night and I know a lot of people were out and about and we are receiving good information from them," Detective Inspector Greg Williams said.
Police have spoken to a second client of Mellory's who picked her up at around 10 pm. "Mellory directed him to take her to a car park behind an abandoned building in Chester Street East. We know that she was dropped off back at Peterborough Street at around 10.20 p.m.
"Taking into account a number of factors I believe that it is likely that Mellory was picked up again at about 10.35 p.m. and we are yet to identify who that person was but I am confident we will identify the vehicle used."
DI Williams said Police had a possible sighting of Mellory standing at the corner of Peterborough Street and Manchester Street at about 10.30 pm which is consistent. "We are still working with this witness to firm up the time.
"It appears likely that Mellory was picked up at 10.35 pm or very close to that. To date the person who picked her up has not come forward. This is time we really are focusing on."
DI Williams said people travelling on Dallington Terrace around 11.10 pm saw a white saloon vehicle parked on an angle on the grass between the river and road around about 72 Dallington Terrace.
"This witness also saw a young male, mid 20, light brown hair, walking along with his hands in his pockets towards Mc Bratney's Road and a larger car like a four wheel drive or ute with two males standing beside it parked close to 43 Dallington Terrace. One of the males is described as wearing Camo patterned knee length shorts. We would like to hear from those people as they might have seen something."
DI Williams said also that while Police have talked about Mellory's watch stopping at 10.59 they cannot rule out that something has happened past this time.
"I also want to talk about the actions of the offender. I believe that the offender has used a vehicle to pick Mellory up in. I would expect that they have spent sometime in and around the area prior to picking Mellory up and may well have been there leading up to last Thursday.
"After the event the offender may well have stopped using the vehicle for no apparent reason. They might have asked a friend or associate to store it. They might have altered it or changed the tyres. Obviously they were out and about at the relevant time and this might all add to the picture."
DI Williams said it is hard to say how someone might react afterwards. "Sometimes they might be struggling with what they have done and seek help or tell someone and sometimes they might not do anything apparent. We can't rule out also that they might have been injured themselves during the attack.
"I ask any one who might have any suspicion about anyone like that then let us know and we will ensure your confidentiality."
Attached to this release is a photograph of an Alltrade brand pocket knife that was found on the riverbed close to the body. When it was found it was shut. "Mellory's partner says that he has never seen it before. At this stage I believe it hasn't been used to cause Mellory's injuries but we still want to identify who it belongs to. It is currently being subjected to forensic tests."
ENDS