Police have decided not to lay charges against anyone at a Southland special school over the alleged use of a seclusion room.
A parent, Victoria Turnbull, complained almost two years ago about undue restraint of her nine-year-old son at Ruru Specialist School in Invercargill.
The principal has said the staff had declined to be interviewed by the police.
Police said in a statement they have finished investigating allegations of assault and unlawful detention at the school.
They said they took the complaints seriously and investigated fully and found no evidence to support any criminal charges.
In a letter to parents today, Ruru Specialist School principal Erin Cairns said she was pleased the investigation had confirmed the findings of an earlier investigation.
Ms Cairns said the school's policies were fully in line with the old Ministry of Education guidelines for behaviour management, and they were entirely in line with the ministry's new ones as well.
She said the school was fully co-operating with a separate inquiry by the Chief Ombudsman.
Chief Ombudsman investigating seclusion room use
Ruru Specialist School is one of eight schools at the centre of the special investigation by the Chief Ombudsman about the use of seclusion rooms for pupils with difficult behaviours.
In a letter to parents last year, Ms Cairns said the "safe room" had not been used since the time of the complaint. She said it was not a seclusion room, was not used as a punishment and it was just a room off a classroom with a large window.
In November, Education Minister Hekia Parata told Morning Report that, though there was only a "very small handful" of schools using seclusion, the law was unclear.
"So I want to make it unambiguous that seclusion rooms and the practice of seclusion is not acceptable and will be made illegal."
She later revealed that 17 schools across New Zealand had used seclusion practices that year.