I could possibly see one lone gunman - I mean, the yearly visits to ensure that my brother-in-law still has Downs is just a total waste of time, and always they choose the only time that is convenient for them. Of course, you miss that appointment, they immediately shut down his SDI (and almost always seize the funds in the account.)
But a group attack? There was a county banquet going on at the time of the attack, but a bizarre target if that was it.
That was my thinking. His disability got taken or he got fired and he went postal.
Would be a perfect, “emotional” soft target. Evil