Dr explains how shooters act before they attack

• The former chief research psychologist for the U.S. secret service Dr Marisa Randazzo has stated that most school shooters act the same way before they attack.

• Most school shooters plan their attacks a week, month or even years before they carry out the shooting.

• Second, most of the school shooters are seen to be despondent or even suicidal when they carry out their shootings.

• The school shooters tell other people about their violent plans before they carry it out.