As we have reported, the F.B.I. advises active shooters engage in pre-event leakage of violent intent. This is precisely why we advocate for such things as safety education and reporting systems (traditional and anonymous) for victims and witnesses to direct their concerns as a critical violence prevention mechanism.
Other recommendations for prevention include strong anti-bullying standards, policies and procedures and the 3-3 Pledge.
Multiple media sources report the accused shooter at the STEM school in Colorado where one student was shot dead and eight others were wounded talked about shooting up the school to fellow students and also bullied younger students at the K-12 school before the May 7, 2019 attack.
In cases of school shooters, the F.B.I. advises leakage of violent intent will be shared with fellow students and teachers.
Prevention is the only solution.
A Study of the Pre-Attack Behaviors of Active Shooters in the United States. F.B.I. Report. June 2018.