Ngahau began "favouring" him, asking him to stay late. Raised to respect elders and not to question them, victim one told no one when the abuse began in a back room of a classroom, starting with kissing and fondling, then growing worse.
"He made me afraid to go to class . . . I can still vividly remember the scent of your aftershave, which I think was Old Spice."
The victim remembered how, when he tried to call for help, Ngahau covered his mouth with his hand.
He left school early, and the lack of further education has impacted his life ever since, Ms Pollett read.
"I have never forgotten those incidents. They have haunted me.
"I can see them in my mind's eye as vividly as the day they occurred.
"I thought about taking my own life after each incident."
The second victim was also abused at school, being touched on the genitals in class. Ngahau moved to another town.
The third victim also had his impact statement read out in court, talking of how he has had to work through the trauma of being abused, which meant he had to go on the sickness benefit. Victim three, unlike the other victims, was not a student at the school.
He came forward about the abuse after the charges relating to the other victims were made public.
Ngahau had pleaded guilty to all charges and, in court, sat in the corner of the dock with his head bowed, leaning on his wooden walking stick.
Lawyer Tony Balme spoke of Ngahau's medical conditions, holding up a bag the size of carry-on luggage full of Ngahau's medical supplies. "It's a heavy bag."
Mr Balme said since his offending had come to light, Ngahau had virtually locked himself in his house and "found it difficult to emerge". "He is intensely conscious of his place in the community and the shame he has brought on himself and the shame on others - his wife, his whanau, his iwi."
A kaumatua of a Kawhia marae spoke on Ngahau's behalf about how the family expected Ngahau to pay for his crimes, but would always support him.
Judge Rollo took Ngahau's early guilty pleas into account when sentencing, as well as his age and his health, but also acknowledged the substantial breaches of trust, the vulnerability of the victims, the repetition of the incidents, the long-lasting effects on the victims and the level of premeditation.
As the offences were historic, the judge had to sentence Ngahau according to the laws of the time.
After sentencing Ngahau to prison, Judge Rollo said there was little more that could be said.
"What you have done has been a terrible thing to young persons who were in your care."
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Samaritans 0800 726 666
• If it is an emergency and you feel like you or someone else is at risk, call 111.