An excerpt of a paper I offered for review: Interestingly, most shooting incidents have taken place since Congress passed the 1994 Safe and Drug-Free Schools and Communities Act.
Also schools surveyed as having the most crime also, in some instances, had the most security methods in use. Yet, according to reports by the Secret Service, over-reliance on physical security can be useless and even dangerous.
Again, there is no single profile in appearance or action that will expose a shooter in the crowd. Yet most shooters do not just snap. There is usually a buildup to the final act. Some have indicated they planned the act weeks in advance. Violence is the end result of a process.
One reason all shooters have been males could be the way we raise our men in America. Some psychologists believe we predispose our males to a sense of loneliness, sadness, and disconnection. Consequently, they do not communicate much with those who could possibly offer a better method of handling pressure situations they are frequently subjected to. With violence being so prevalent in their world (video games, movies, etc.) they feel it is the only way to alleviate situations they face.