The question of whether law enforcement and mental health professionals hadn’t failed in their duty to their communities by failing to forcibly detain those who would go on to commit mass shootings has been raised after most recent episodes of such violence.

“If only the police had put him in a 5150 hold.....” one Twitter user lamented. Even Santa Barbara Sheriff Bill Brown was second guessing himself on CBS’s Face the Nation, saying he wished "we could turn the clock back and maybe change some things,” implying that given a second chance his men would have detained Rodger for a mental health evaluation.

Adam Lanza had therapeutic contact with mental health professionals before he went on to shoot up Sandy Hook Elementary School. James Holmes was seeing a psychiatrist before he went on a killing spree at an Aurora, Colorado movie theater in July of 2012. Before Jared Loughner shot Gabbie Giffords near Tucson, Arizona he had raised red flags at school, where teachers reported that he had become increasingly bizarre, delusional, and threatening in class.

So why didn’t law enforcement detain Elliot Roger, or any of the other recent mass shooters who had some contact or had some concern raised about their wellbeing before they went on to kill? It seems obvious after the fact that such an intervention could have prevented unfathomable tragedy. Why do we fail to intervene?

In the case of Elliot Rodger, based on the description given by the Sheriff Bill Brown at Saturday night’s press conference, it’s hard to argue that they should have done anything more than they did. Trained in mental-health response calls, the officers arrived to find Rodgers not fitting the criteria they would normally use to take someone involuntarily into custody for a mental health evaluation. Officers said that they found him lucid and articulate, saying that he had no intention of hurting anyone. They said that he was shy, but shyness isn’t indicative of unstable mental health. They probed enough to find out that he was lonely and having problems in his social life. But being a loner is no more an indication of unstable mental health than shyness. And the criterion for involuntarily holding someone, while they may differ some from state-to-state, are usually very clearly defined: Does the person pose an immediate threat to themselves or the community (As in, do they actually verbalize, “I am going to kill somebody or myself and here is my plan for how to do that”?) If not, the right thing to do, which the Sheriffs in this case did, is to not detain someone.

This fact has begun to frustrate a public grown weary of mass shootings where mental illness may be a contributing factor. After previous mass shootings, there have been calls to ease the strict standards guiding involuntary mental health treatment to give authorities greater ability to detain and compel the treatment of mentally ill people they fear could become a risk to the community, even if they aren’t imminently one at the time of their interaction with the person. In The National Review, David Gratzer wrote after Jared Loughner’s 2011 Arizona rampage, “Before the 1960s, psychiatry was largely unrestricted by patient rights. In the past four decades, the pendulum has swung to the other extreme … Arizona is a tragedy. But perhaps it will inspire us to reconsider the rights of the severely mentally ill, and our responsibility to them.”