Police are now treating an earlier blaze at a Bury St Edmunds secondary school as arson.
Suffolk Fire and Rescue were called to the County Upper School, in Beetons Way, at 3.24pm today, October 28.
Three engines attended the scene where a pile of insulation material had caught alight.
The materials were next to a container being used as a tea room.
The flames did not spread to the main school building and fire fighters were able to extinguish the flames soon after.
Both parents and pupils have been reassured that it was unaffected.
Police have this evening arrested three females and they remain in custody.
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