Three Far North schoolboys are facing criminal charges after a violent episode at Taipa Area School.
Kaitaia police were called to the school on Wednesday after a 14-year-old who'd been stood down attacked the principal's car - bashing in windows and panels, and stabbing the tyres.
Police said the boy handed his weapon to another boy on the school bus and took off.
Officers who boarded the bus were attacked, and used pepper spray before wrestling the second boy and his brother to the ground.
The three will appear in the Kaitaia Youth Court next week.