The fire that broke out at the Musaeus College auditorium in November was determined as an act of arson, sources at the Government Analyst Department said.
An official at the department said that the investigations had revealed the fire was caused by someone setting fire to the backstage of the auditorium after dousing it with kerosene.
A major part of the auditorium was destroyed by the fire.
A report had been handed to the Cinnamon Gardens Police by the Department for further investigations, the source added.
The school auditorium was set ablaze on November 4, 2016. There was no casualties