I'm not trying to start an argument about mental health here enduramil, but I'm an RN at SPH and I work with many people with mental health issues on a daily basis. I'm not just reading internet news and spewing second-hand opinions.
I am guessing you are also someone with a connection to mental health in some fashion as well, based on your comments, so I'm not going to argue.
But you are not helping with the knee-jerk assumption that because they have demonstrated they are a danger to society, they must have mental health issues. The corollary assumption being that everyone with mental issues is dangerous.