<i>Incidents like this are not common in developed nations.</i><p>You mean like those comprising Western Europe, and, say, include Canada to pile it on?  The former has had more of them in recent decades than the US.  Here&#x27;s the detailed accounting I did for Western Europe 2+ years ago: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=4970408" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=4970408</a> and with more discussion: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=5070201" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=5070201</a><p>Wikipedia seems to have rearranged their previous lists that made this a lot more clear, but see:<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_school_massacres_by_death_toll" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_school_massacres_by_de...</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;School_shooting#Notable_school_shootings" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;School_shooting#Notable_school...</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_rampage_killers" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_rampage_killers</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_rampage_killers#School_massacres" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_rampage_killers#School...</a>