Police are investigating a suspicious overnight fire at a vacant school at Smithfield Plains.
About 10.45pm on Monday 13 January, police and fire crews responded to reports of fire at the old Smithfield High School.
The fire caused damage to one of the northern buildings before being extinguished by MFS.
Crime scene investigators will attend to examine the scene this morning.
Anyone with any information is asked to contact Crime Stoppers on 1800 333 000 or report online at www.crimestopperssa.com.au
The vacant school was also damaged by fire on Sunday 8 December.