Firefighters have ruled the fire was caused by arson after finding accelerant on the scene, Muir said.
"The fire was ruled arson," Muir told City News Service. "We do not know if this person lit the fire."
The fire that began around 6:30 a.m. -- half an hour before the first class -- on the third floor of the campus business/general studies building caused $200,000 in structural damage and $200,000 in lost content, Muir said.
The damage was mainly confined to that lecture hall, Room 356, the fire captain said.
Although the fire began near an air conditioning unit, the air conditioner did not cause the fire, Muir said.
Classes in the second and third floors of the building have been relocated and will resume Tuesday. Check here for a list of relocated classes.
-- Additional reporting by City News Service