not2cleverRed
Obvious Observer
While that's possible - I was that sort of kid - I also knew kids growing up whose parents were snowed into believing their children were choir boys. Well, actually, the neighborhood choir boy (literally!) started rock throwing fights and set fires in the woods, but his parents always thought him innocent. (All the moms in my neighborhood were convinced their on children were angels, except mine - my mom was the only mom who could accept that her kids might get into mischief.)Its not unheard of Zig for one child in a group to choose not to participate in the idiocy that the rest are doing. There are some children that do understand the concept of cause and effect...LOL.
OP has the issue of their child being considered financially responsible. Contacting their insurance is a good idea, but finding people to share the burden of the financial blame wouldn't be a bad idea either. I strongly suspect that the other 3 boys with mystery contact info either aren't that mysterious, or else ALL adults involved are completely irresponsible. There were 5 boys, it should be split 5 ways unless one of the boys demonstrably caused more damage than the others.
OP wants to get back by showing that the other parents were irresponsible about the BB gun. I think that's a less useful approach to the situation.