Port Elizabeth police are investigating a case of Arson following a petrol bombing incident at Arcadia Senior Secondary School in Bethelsdorp.
Colonel Priscilla Naidu says the security guard at the school heard the sound of breaking glass around 8.20 PM.
Two men were seen running away and the guard then realised that a petrol bomb had been thrown into the principal's office.
Colonel Naidu says the guard managed to extinguish the flames with a fire extinguisher before any damage could be caused.
No arrests have been made.