Nearly everyone who goes on a killing spree at an educational institution is a lone male in their teens or twenties. Except the latest massacre seems to have been performed by a married middle aged woman.
This is a reason to be sceptical about the efficiency of profiling in counter terrorism, sure most terrorists fit a certain demographic profile but not all do and if the focus on those that fit the profile is too strong it can easily result in everybody else getting a pass.
West Bay station, Bridport, in 1982
50 minutes ago