Waitemata Police have announced the reopening of an investigation into the murder of Tracey Ann Patient in Henderson, 40 years after the 13 year-old girl disappeared while walking home from a friend's house.
Ms Patient's body was found by a dog-walker in a bush on Scenic Drive, and evidence suggested she had been strangled with a stocking.
An extensive investigation into the murder was launched for the few months following the discovery of her body, with 850 people profiled in the hope of finding the killer -- but nobody was charged with her murder.
Police had an anonymous phone call nearly two years after the murder telling them that Patient's signet ring was in a rubbish bin outside an Avondale chemist, but the caller gave no other information.
This morning police announced they have been working full-time on an investigation into Patient's death since November 2015, with eight investigators at the Watakere Police Station following new leads.
The investigators have made enquiries with an array of people over the last three months, including some in Australia.
"Despite 40 years having passed, someone out there knows who did this," said Waitemata Detective Inspector John Sutton.
"To this day we still have people who ring us with information, and I'm pleased to say we are following new leads.
"The West Auckland community remember this well. It was horrific; a 13-year-old girl with her whole life ahead of her, just minutes away from home and brutally murdered.
"Someone out there knows who did this, and we are as determined to solve it now as we were back then," he said.
Police are asking the public to pass on any information about the case by calling 0800 000 111.
It was Thursday January 29, 1976 when Tracey Patient went missing.
She had been at her friend's house in Chilcott Rd, Henderson prior to the disappearance and was due to return to her Dellwood Ave home around 9:30pm.
Tracey's friend had only walked with her halfway home, and the pair separated at the intersection of Great North Rd and Edmonton Rd.
She was last seen outside 295 Great North Rd, and the following morning Tracey was found dead in a bush after having been strangled with a stocking and dumped on Scenic Drive, Waitakere.
Today police released heart-breaking video featuring Tracey's sister speaking out about her sister and the case that brought New Zealand to a standstill.
In the video, Debbie explains how her mother had given her permission to head to the Doobie Brothers concert the night of the disappearance despite being grounded.
It was because of this that Tracey was also given permission to go out -- hence why she went to her friend's house.
Debbie explains how when she and her sister parted ways that evening before the concert, she had no idea that it was going to be the last time she ever saw Tracey alive.
It is going to the concert that Debbie defines as the "regret of her life."
"I just so regret not turning around. Looking back, how are you supposed to know that's the last time you're going to see somebody?" Debbie says.
Later that night, when Tracey hadn't returned home Debbie says she went in search for her sister across Henderson with her father.
"She was about a half-hour later than she was supposed to have been and Dad and I went out in the car. Just went around Henderson and the town just looking."
In the video, Debbie also explains how the next day they were sitting in the living room with her mum and her 8-year-old sister Denise when her dad came home.
When they asked their father where Tracey was she says he broke down in tears.
"Denise asked 'when is Tracey coming home' and Dad said 'she's not'.
"We were like, what do you mean she's not? And he said someone killed her."
Debbie admits the aftermath of such an event was hard to come to terms with.
"I just kept thinking she was going to come walking up and go, 'Ah, fooled you, it's a joke'.
"Then every night-time you go to sleep, wake up in the morning, and it's about two seconds before you realise, and it's like ah, you think you've had a dream or something. [It's] just awful; so so hard to cope with."
Debbie admitted she hadn't forgiven the killer, and that she hoped they'd had an "awful, awful life."
Watch the video above, provided by Waitemata Police, for further information on the case.