THE Arson Squad is still investigating a fire that destroyed a demountable classroom at Davallia Primary School in Duncraig on Sunday.
Police and fire crews attended the school about 11.10pm.
Investigations led police to believe the fire was deliberately lit.
It took 15 firefighters about 20 minutes to contain the blaze, which caused an estimated $100,000 damage.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000.