Two buildings in Central Queensland were destroyed when a blaze broke out at the middle of the night.
Fire crews were called to the Fairymead Mill, north of Bundaberg, just after 2am on Wednesday.
Large plumes of smoke were billowing out of the buildings when crews arrived at the fire, which police say may have been deliberately lit.
Nobody was inside at the time and the blaze was brought under control by firefighters within 45 minutes.
Firefighters remained at the scene until about 6.30am on Wednesday to fully extinguish the inferno, before leaving the building under police guard.
Forensic investigators were on scene on Wednesday