The Blocked Open School House Door
...the shooter didn't get out of his truck and walk round and round the school looking for an open door. He seemed to wreck his truck and walk straight to the door. IMHO, somebody either left the door open for him or made a regular habit of blocking the door open and he knew about it either thru observation of his target or he just got lucky. In either case, that is one part of the investigation that should be followed up on.
Liberals are like a "Slinky". Totally useless, but somehow ya can't help but smile when you see one tumble down a flight of stairs!