So my friend set something on fire...?

My friend set a tube at a playground on fire, well not really on fire but he left is singed (burnt) a little... i was with 3 other people and me and another guy stayed back and told him not to (but he did anyway) (BTW he used gas/oil to burn it so basiclly only the oil burnt but still... its bad) If he gets caught and rats us out (or the other way around) and we tried to stop him, will me and my other friend get in as much trouble as he did?