In 'Stand on Zanzibar', John Brunner coined the word: "muckers". This describes someone who flips and engages in a seemingly random and purposeless act of violence usually in a crowded placed like an airport, high street or, dare we mention it, school. The word - in Brunner's etymology was a corruption of the word "amok" which we know and define as:
...behave uncontrollably and disruptively
But more importantly, the derivation of "amok" is:
...mid 17th century: via Portuguese amouco, from Malay amok 'rushing in a frenzy'. Early use was as a noun denoting a Malay in a homicidal frenzy
And this was Brunner's usage - a homicidal frenzy. And they've been around for centuries - probably much longer.
So a question - following the terrible events of the last week, we're talking again about gun control. Now while I'm equivocal about such controls, it does seem to me that we should consider why we get "mockers" rather than just the means by which such men run amok?