While police are not seeking anyone else in relation to Zhang's death, they are appealing for information and sightings of a vehicle used by the accused.
Detective Inspector Aaron Pascoe says they are continuing to piece together the events of the crime with the help of the public.
"Thank you to everyone who has reached out to give us information," he said.
"Police are still seeking any sightings of the vehicle, a white 2004 Hyundai station wagon with the registration EGZ962, used by the alleged offender.
"This vehicle has distinctive brown tape around the left rear window.
"We again extend our condolences to Lena's family and reiterate their pleas for privacy at this difficult time."
If anyone has information relating to this case, or sightings of this vehicle please call 105 and quote the file number 210922/0539.
We are shocked by the news of Lena Zhang Harrap’s death. Lena and her whānau are much loved members of our Heart Kids...
Posted by Heart Kids NZ on Thursday, September 23, 2021
The NZ Down syndrome community says the horrific incident is an anomaly and are urging people with Down syndrome not to let it stop them from seeking independence.
"Lena's death has shocked our community to the core and many parents have expressed increased fear and anxiety about giving their children with Down syndrome the independence any person deserves.
"We totally understand this sentiment, but we want to encourage all families not to give into this fear by keeping their loved ones at home," said Zandra Vaccarino, the national executive officer of the New Zealand Down Syndrome Association.
She says Lena was a "wonderful example" of someone who was fully immersed in her local community.
"We know that disabled people are safer when they are participating in their community and not isolated as highlighted by the current work of the Royal Commission into Abuse that has evidenced the extensive level of institutionalised abuse," said Vaccarino, also speaking on behalf of the UpsideDowns Education Trust, ADSA and Down Syndrome International (DSi) .
She also appealed to the wider community to support and respect the wishes of Lena's family to grieve in private.
NZ charity Heart Kids said Lena and her whānau were much loved members of their community, and they were privileged to have enjoyed her bubbly presence at events, camps and coffee groups.
"Lena's genuine warmth and kindness saw her make many friends from all walks of life - she was a true ray of sunshine and will be sorely missed," the charity said.
Social media has been buzzing with messages of shock and support since Lena's death.
Several posts on the Mount Albert Community Facebook page said they were worried about their safety in the Auckland suburb after the horrific incident, while others suggested lighting a candle in Lena's memory.
"Why in 2021, can't NZ wāhine walk without fear wherever, whenever - a dark carpark, a late-night dog walk, from the bus stop at dusk … or now up our Maunga at 7am?" asked Liz Lyons.
"Lighting a candle seems to bring some peace and light to this dark space," read a post by Sally Rayner.
"Many of us are feeling very emotional at the moment ... ask yourself, 'what would Lena do?' Turn that energy into going for a walk and smiling, saying hello to as many people as you can, making their day brighter ... into making a donation, no matter how small," said Caroline Ciacca Church.
A Facebook page MAC Wāhine/Women page was set up on Friday night for women feeling unsafe in the community and wanting to share experiences, warnings and support after Lena's death.
More than 300 members have joined as of noon today.
