The Case Is Closed

A pre-teenager servant boy dies of carbon monoxide poisoning on a cold winter night. He was employed by a young working Calcutta couple with a small boy of their own. Taking money from a neighbor's friendly daughter, he slipped away to watch a movie on a cold winter night. Finding his usual sleeping corner below the stairs too cold, he bolts himself inside the kitchen, where a fire was burning. The next morning we witness a powerful discovery scene like on the morning after Macbeth's murder. The door is forced open and we see the commotion in the apartment block which is the stage of the drama. Who is responsible?