A person can walk into a gun store, he appears to be normal, he strikes up a conversation with the shop owner. The Shop owner has no idea if he has a mental illness or not. A week later the gun is used in a shooting. This is not about the gun or where to get a gun, it's about it being very hard to tell whether someone is disturbed enough to be homicidal. Like that Elliot Rogers kid who suddenly snapped, who knows how long he was bottling up those emotions. I don't think mental health clinics or whatever they are called are doing enough. What do you think can be done about this?