So there should be an investigating on that room that caught fire.
1 - the workers that helped Suneri to putout the fire said "this is a fire that is due to oil and will not be put out with water and they will need sand" and that is what they used finally to stop the fire.
2. A dry room fully to get drenched in an oil there should be more to it.
So if a proper investigation is carried out forensic evidence will prove that the whole room reeked of Ghee.
And then it would lead to how the ghee got there and would the suspected person have the opportunity to dab ghee in an entire room.
And it should open up another side - cz the only person who might have the time, authority and opportunity is Mohini.
Anyway i might be expecting too much logic here, but still a police/BSD investigation of the fire n the cause wouldn't be too much to ask, would it?