Police searching for Mellory Manning's killer believe they have pinpointed the time the attack on her was likely to have started.
It has been almost one hundred days since the Christchurch sex worker was brutally beaten and stabbed to death.
At 10.43pm on the night she died, Ms Manning sent a text message indicating she was with a client, and then switched her cellphone off less than 50 seconds later.
The police say Ms Manning would not have turned her phone off without some duress, and they believe it could be the catalyst for the attack.
Detective Inspector Greg Williams says Mellory Manning had also secured her handbag in a way that suggests she was not comfortable with the person who picked her up.
Her body is thought to have been dumped in the Avon River about 15 minutes later.