How and to Whom?

It seems the advice is "if you see something say something" (serial killer Devin Kelley). How? To whom? Easy to say, hard to do. The lowest scum of the earth in the U.S. has rights that can't be taken away. Who commits a mentally ill person to treatment, and does it work? How do you report a relative who lives under the same roof?   I wonder if Rand Paul had reported his hostile neighbor; did the ex-wife of the TX killer have a worthless piece of paper on file; how many have tried to have a driver's license taken away from an elderly parent--unsuccessfully; a barking dog? Good luck.

http://www.foxnews.com/us/2017/11/06/how-was-texas-gunman-able-to-buy-firearm.html

http://www.foxnews.com/us/2017/11/06/man-hailed-hero-for-chasing-texas-church-gunman-after-massacre.html

https://www.thedailybeast.com/bystander-shot-devin-kelley-twice-before-suicide

http://www.westword.com/news/texas-church-killer-devin-kelley-and-colorado-springs-connection-9667697