The BAU focuses on preventing targeted violence by identifying concerning behaviors. For example, active shooters meticulously plan and prepare for acts of violence. Throughout this process, they frequently exhibit worrying behaviors, characterized as observable and identifiable actions suggesting potential progression towards targeted violence. While no individual behavior definitively signifies an individual's trajectory towards committing targeted violence, the presence of multiple behaviors may warrant attention and concern.
It may come as a surprise that the FBI has been studying the issue of School Shooters for some time now and have published a document: The School Shooter: A Threat Assessment Perspective. Now this document is over twenty years old as a preface is provided by Janet Reno and is based on work beginning in 1999, so there has been plenty of time for this information to be disseminated throughout educational and security communities.
Perhaps it has.
It certainly has not made an impact on mass media with the FBI noting that "[n]ews coverage magnifies a number of widespread but wrong [...] impressions of school shooters," citing specific misinformation: "school violence is an epidemic"; and "easy access to weapons is the THE most significant risk factor." [emphasis in the original]. On the contrary they note "[un]usual or aberrant behaviors, interests, hobbies, etc., are hallmarks of the student destined to become violent," which seems intuitively obvious. There is a strong suggestion that biased media coverage also leads to knee-jerk reactions, but counters with H. L. Mencken's aphorism that "for every problem, there is a solution which is simple, neat, and wrong." Fair enough, but perhaps a nod to Occam's Razor is also in order, after all, adolescent Black females aren't shooting up schools. Finding out why one particular demographic seems to predominate should gather the attention of researchers. Regardless, this document is must-read for anyone with adolescent children in schools, particularly public schools. It will keep you up at night and might have you asking pointed questions at the next school open house.
A couple of sections are particularly concerning. The first fright is Family Dynamics with almost every item being a symptom of, or exacerbated by, the newest fad: gentle parenting. Truly terrifying is the section on Personality Traits and Behavior. Most of these are what you would call "teenager," but what might happen is a perfect storm as many of these traits feed on one another. Others are more concerning, including narcissism, entitlement, pathological need for attention, and anger issues, all of which seem to have become increasing issues with adolescents over the years. In addition, media: TV; video games; and the internet are mentioned, maybe even featured. A particular issue is "fascination with violence-filled entertainment," so if your adolescent enjoys watching "Criminal Minds" they very well may have one.