We've got to do something. The present plan is not working, and I've had a couple thoughts - and I know this is the DB Cooper Forum and political/gun violence discussions are far afield - but perhaps a few thoughts shared among friends...
1. Banning assault weapons does work for other countries and might work in the USA, too.
2. Register militias and allow them unrestricted access to all the military ordnance they want except the really scary stuff like, RPGs, 50 cals, C-4 compounds, etc. Insist that militias regulate and supervise their members and the use of their weaponry.
3. Support groups for the weird people among us, like AA for alcoholics or anger management for wife beaters. Kids like Cruz, who cause trouble and are known to the cops, get expelled, kill pets and love guns would be mandated to attend regular groups. Cruz was troubled, and he became an orphan last November when his mother died - his father died a few years ago - and a neighbor took him in. He clearly needed more than that.