"This problem was compounded by a delay in transferring Jordan's case.
"It would appear that a lot of faith was placed in the fact that Mr Lock had been Jordan's primary caregiver for most of his life and was doing a great job as a father figure."
Nothing in Nelson's history suggested he was at risk of committing such violence, Ms Salomen said.
The decision was made for Nelson to live with Mr Lock and Ms Kurth in October last year.
Mr Lock told Radio New Zealand his grandson's CYF file was to be transferred from Hawke's Bay to New Plymouth but that did not happen until March.
He said CYF failed to organise the counselling the teenager needed.
Nelson will serve at least six years before he is eligible for parole, but Mr Lock told RNZ he would oppose any bid for early release.
The teenager allegedly claimed he was upset at Ms Kurth for not allowing him to see his mother, a claim that wasn't true, Mr Lock said.
In court yesterday, Mr Lock read out a victim impact statement saying he felt his world had ended when he found Ms Kurth dead.
"When I returned from crossing that river on that day and saw the two bloody drag marks leading into the spare room, seeing Rose laying on the floor ... I thought my world had ended," he said.
Ms Salomen described it as a "terribly tragic case" and said staff were assessing what needed to be done for Nelson.
