At a parole hearing in September, 2014, he finally admitted he hit Mikara once in the abdomen.
His statutory release date is September 25, 2020.
Concerns Hapuku was yet to tell his family he had admitted the offending were raised in a psychologist's report, the Parole Board's report read.
"Generally the file notes are positive, but deterioration in his demeanour has been noted. Mr Hapuku is said to be sad and unmotivated. He says that he is in a dark place."
The report noted it was thought feelings of shame may partially explain why he hadn't told his family about the admission, and that this disclosure was seen as important to his safety plan.
"Mr Hapuku has had 15 to 20 sessions with a psychologist. He says he got to sit down and really talk about his crime. The safety plan was the biggest part that he enjoyed.
"He identified that his main high risk situation is having no structure. He says that in the past he was all over the place but now he will work with whānau and the Probation."
The board noted Hapuku said with regard to the gang that it would always be there as it was his whanau but believed he could stand up to them now.
The report stated he had been employed but this was terminated after a three week absence.
"He has a sporadic work ethic and health issues. Adding to his stress have been whānau issues.
"He said that he was removed from the grounds maintenance team as he was going through a bad patch. He tried to handle it himself."
His plan, if he got parole, was to attend a course and he was interested in forestry, the report read.
"His whanau is supporting him in getting that organised. If he remains in prison he is not sure about the way forward. He will consider making an application to work outside the wire and release to work.
"He says that he was working outside the wire for five years but never made an application for release to work as they do not have the jobs that he would like to do."
Hapuku will be seen for further consideration of parole in August, 2018.