Child, Youth and Family spent nearly half a million dollars to try to turn a troubled teen into a functioning member of society, but it wasn't enough to stop her committing murder.
Tonya Bennett was given her own house, a caregiver 16 hours a day and endless attempts were made to counteract her unstable behaviour.
But when she was just 16-years-old she doused a sweatshirt in highly-potent alcohol and set fire to her ex-boyfriend's home, aware that his mother, Lynette Chapman, was asleep upstairs.
An inquest into Ms Chapman's death concluded yesterday in Auckland District Court, which was told that Bennett had been on CYF's radar since she was nine-years-old when she began displaying behavioural issues that her parents were unable to manage, and she was placed under CYF guardianship in 2006.
After absconding from numerous caregivers and regularly appearing before the courts, Bennett was relocated to a house on Wellington St in Pukekohe, which was rented specifically for her in September 2008.
CYF northern regional director Sharon Thom told the inquest that a total of $495,000 was spent on Bennett's care between 2006 until 2012.
"Most young people are able to have their needs met within the bounds of regular services.
"Ms Bennett was therefore an extraordinary case and required a level of support far above the norm," she said.
Bennett entered into a relationship with a teenager who lived down the road, and they went out for a few weeks before he sought to end the relationship, which she was not happy about.
On January 19, 2009, she and a group of friends got drunk at her house and, with 18-year-old Michael Cartwright acting as lookout, Bennett went to her ex-boyfriend's house and set it alight.
She later told police that she knew Ms Chapman was home by the sound of the television upstairs.
In 2010 she was sentenced to 11 and a half years imprisonment after pleading guilty to murder and two counts of arson. Cartwright was jailed for two years for manslaughter and arson.
The inquest was told the caregiver charged with looking after Bennett on the night of the fire had brought her two young children with her, in breach of YouthLink's rules, because her husband was working late.
Ms Thom said this may have compromised her ability to be as watchful as she could have been with Bennett.
The caregiver, whose name is suppressed, had also failed to obey YouthLink's "crisis plan" if Bennett came home drunk, which required her to tell her to go to bed and to contact police.
Neither the caregiver nor YouthLink chief executive Alan Newman were able to clarify whether the woman had received any training while she was employed by the organisation.
Ms Thom pointed out that in addition to the caregiver, CYF social workers were also regularly involved with Bennett.
Speaking outside court, Ms Chapman's father Bob Hunkin said the system had failed in the way it dealt with Bennett.
"She [the caregiver] wasn't qualified but I wouldn't start blaming her. She did the best she could under those conditions, but she was not capable of handling it.
Mr Hunkin said his family and Ms Chapman's three sons were relieved the inquest was over.
"Hopefully that's the end of it and we can get on with our lives," he said.
Coroner Morag McDowell reserved her judgement.