I was a little rushed, let me add some more. Here are some criteria.
Tortured animals, or humans.
Threatened Family members or others.
Referral from mental health professional.
Referral from from family member.
These trigger a simple response, a minimum of two psychologists(three might be better), examine the subject and determine if the are a danger to society.
If the answer is yes from only one, another Mental Health professional is involved.
Two yes's get you locked up until it can be determined more conclusively whether you are a danger.
Is this perfect? No.
Is it better? YES!
In almost all of these cases there was ample warning that these people were disturbed and dangerous.
Let's replay Sandy hook first. When Mom determines that he is" slipping away" and tells the babysitter "don't turn your back on him" she is clearly aware he is dangerous. She refers him. It's obvious to everyone concerned that he is dangerous and needs help, bang, he is behind bars, everyone is still alive.
I'm basing this on that a Mom, who never wants to see the bad in her child became aware of this, surely especially with her help it becomes an easy call for a trained person.
Now lets talk about the Aurora Movie theater rampage.
This was reported http://abcnews.go.com/US/james-holme...ry?id=16943858
Here are some excerpts;"The psychiatrist who treated suspected movie-theater shooter James Holmes made contact with a University of Colorado police officer to express concerns about her patient's behavior several weeks before Holmes' alleged rampage, sources told ABC News."
"Fenton would have had to have serious concerns to break confidentiality with her patient to reach out to the police officer or others, the sources said. Under Colorado law, a psychiatrist can legally breach a pledge of confidentiality with a patient if he or she becomes aware of a serious and imminent threat that their patient might cause harm to others. Psychiatrists can also breach confidentiality if a court has ordered them to do so."
Notice the mechanism is already partially in place, and It's what they are already trained to do.
Notice as well what I've been saying from the start, the system as presently constituted, is utterly incompetent when dealing with these situations.
What I'm describing here is not that expensive, in my experience the people caught in this net would not be many. 100-200 per state per year at most. Fund it however you want.