When I was younger I used to work at a liquor store with a firefighter. I asked him about arsonists since we had 3 whole trailer parks go up in flames. He told me they always had someone in their civis and would wonder thru the crowds or people parked nearby. He said there were a couple of fires where they caught the guy because I quoting here that he would jerk off to his fires. But one time I guess he did the fire wrong and burnt the shit out of hit nether regions and when he went to the hospital they reported it.