Officer Killed in Davis I'm a retired mental health professional. Over the course of my career there were numerous times when I worked with individuals who were downright "scary" because of their mental health issues.
The California Tarasoff law requires psychotherapists and other mandated reporters to warn identifiable potential victims of a serious threat of harm and to notify the police of the same when the threat of violence is met under the guidelines of the Tarasoff law. I only had to do that twice in my career, but I can not tell you how many times someone "felt potentially dangerous" to me but the situation did not meet the all of the strict mandates of the Tarasoff law necessary for me to be able to break the legal confidentiality of the potential perpetrator.
Those cases were always the most stressful for me because there is a fine line between required reporting under Tarasoff and breaking the legal confidentiality of the potential perpetrator. Thank god I never woke up and opened the paper with a headline about a client of mine having committed some heinous crime but there were times I worried that that was a real possibility.
Perhaps I am jaded because of my professional experiences but there are a lot of people out there that live on the edge of potential violence. The fuse is already lit and has been simmering for a long time. It's just matter of if and when they might explode. If that happens and, especially if they have access to assault weapons, it can be potentially horrendous. There are red flags but, unfortunately, no sure way of predicting such violence.
http://jaapl.org/content/34/3/338