Charges are yet to be laid over a fire that tore through a building at Comet Bay College in Secret Harbour.
The fire started in the English and Humanities and Social Studies building at the high school on Thursday night.
It damaged several classrooms and forced the closure of the school on Friday.
Parents were also asked to keep their children home on Monday except for Year 11 ATAR students who are taking exams.
A 15-year-old boy was taken into custody but has since been released.
It's understood he is undergoing medical treatment.
The investigation is still ongoing.
It's not yet known when the school will reopen.
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