A Hamilton youth escaped from Oranga Tamariki supervision yesterday afternoon and made their way to Fraser High School, triggering a lockdown.
Principal Virginia Crawford told parents the young person presented a "real and present danger to our students and staff".
As soon as the school was informed the youth had absconded from Oranga Tamariki's supervision, police were called and the school went into lockdown.
Staff and students remained in lockdown as police engaged with the young person, who was then taken back to Oranga Tamariki's care.
"The young person is not a criminal," Crawford wrote.
"They require health care and support.
"The young person needs help right now."
Police were called at 1pm after the youth because verbally abusive, after which the school management chose to lock down the school, a police spokeswoman said.
"Police attended and there were no further issues," she said.
Fraser students were reminded they could act respectfully by not engaging, mocking, or making derogatory posts on social or other media about the youth involved, she wrote.
Worried parents were told by text about the school lockdown, which eased shortly before 3pm.
Parents were urged not to go to the school.
The anxiety was heightened for some, as the text from Fraser High School warning of the lockdown didn't include the name of the school involved.
"I am very sorry for the additional worry to our parents and caregivers who have children at various schools, wondering which school had sent the text," Crawford wrote.
In future, the name of the school involved in the lockdown would be included at the start of the text message.
"Some of our students may have been very affected by the lockdown," Crawford wrote.
"We encouraged those students to seek support and care from the Hauora Centre, where our wonderful counsellors and nurse were prepared to support them."
Crawford applauded the school's staff, parents and students for remaining calm.
She also thanked Oranga Tamariki supervisors for promptly notifying the school, the police for their quick response, and the Ministry of Education for offering support and guidance.
Fraser High School staff and students have practised a school lockdown drill as part of the school's normal emergency drills, though the school reviewed yesterday's lockdown and would implement improvements.