Oh, radio flyer, I feel so bad for you. I watched the same thing happen to my next door neighbor 15-20 years ago. Somebody hated him/a member of his family. We had only just moved in a few months earlier when someone murdered his dog in his backyard (from our yard). And they broke into his daughter's car, their shed, etc. on different occasions. His kids from a previous marriage had never quite made it in life and he was trying to help them.

I hope your son calms down soon and sees how things can't get better keeping up whatever feud there is.