This is pure specultion on my part; but I'm guessing that the reason whoever sent you the letter said that your son "did not act maliciously or intend to harm" was to squelch any notion that your home owner's carrier may have of asserting a policy defense. I'm sure that all home owner's premise and personal liability coverages include an exclusion for intentional acts. There's a big difference between malice and negligence. If someone is claiming damages due to the negligence of you or someone in your household, and you've got home owner's insurance I would report it to them and let their experts sort it out. If you don't have insurance they will probably go away. Of course sporto gave the best advice so far: you shouldn't be taking advice from a bunch of knuckleheads (myself included) on a sports message board. Good luck, and I hope everything turns out alright.