Ugh! I hope you find out who is doing this. At least your HOA is attempting to do something, mine wouldn't.
Our neighborhood had the "trash can pyromaniac" a few months back. That was fun getting woke up at 2am by a neighbor and seeing everyone's garbage can on fire. Real nice to have to clean up burnt plastic off your driveway too.
I hope you find out who the culprit is or at least they get scared and stop doing it.