Exactly!! Having worked in a big city ER for 20 years,an ER that was located a couple of hundred yards from a large state psychiatric hospital,I could tell you stories about psych patients that would make the hair on your toes curl.
I wonder how much you read can be believed? Not all troubled kids commit such crimes either; had them as students myself over the years. I’ve had gun vaults all my life, combination in my head. Would have a gun safe prevented this or maybe then he might have just made a pipe bomb or used gasoline. So many questions, no easy answers. Remember, more people are killed by lightning than mass shootings.