If you don't want to read all of Arendt's book, https://www.bbc.co.uk/history/worldwars/genocide/nazi_genoci... and https://en.wikipedia.org/wiki/Sturmabteilung#Rise provides some details of the violence before and during Hitler's rise to power.

This line in particular is frightening:

> They thought that the Nazis were just another right-wing, nationalist party and that Hitler would be 'tamed' by power.