User blog comment:AltertheSilverBird/Total Drama: Danganronpa Chapter 14: Class Trial Part 2/@comment-26184706-20171022042656

I'm gonna guess Duncan, given that the gasoline was mostly found on the truck he 'owns'. As for the whole hidden room debacle, I'm not too sure about him, but he had the easiest access to gasoline so by association it has to be Duncan.