EDIT: I see my post is being downvoted. I know that it may come across as insensitive to immediately leap to the gun control debate, but frankly I'm more angry than upset by this news. How many times does it have to happen? We have a good 48 hours of emotional outpouring and then everyone forgets it ever happened.
How many times are we going to find out someone had a history of mental issues and nothing was done? How many people are reluctant to take proper medication because they view the effects of the medication worse than what it trying to treat. We have a lot of people coming back with PTSD, we need to get better at this.
I remember OK and that was farm products (which some companies still sell at automated machines). IEDs, pipe bombs, propane canisters, Molotov cocktails are all capable of killing a lot people and are easier to build or acquire than guns.
Regardless of ones position on guns, it's almost universal that not nearly enough who need mental health care get it. And, our national attitude is still one of "Therapy is for crazy people!" - yeah, just like "the ER is a viable form of preventative healthcare" and "you only go to the mechanic when your car is on fire".
I'm a libertarian but in practice I'm not sure of a solution that isn't more government involvement.