Mattresses are made to smolder, not burst into flames. It's done with chemicals to protect us against dropping a lit cig. (another way they are killing us)
Here's what happened: they awoke from their drug induced embrace in a smoke filled room. One of them had been or still was on the corner of the bed, passed out backwards. That's where the pipe/tin foil/matches/lighter fell on the bedding. They then ran out side screaming like a couple of girls. On the way out the dominican tried to "save" some valuables, and threw them in the bushes. Took awhile for management to show up and help extinguish the fire. Before management showed up, he concockted the "we just got home and there was an electrical fire!" story.
Case solved. How'd I do Matt?