Warning: Articles contain some graphic but necessary images.
https://en.wikipedia.org/wiki/2001_Raid_on_Armando_Diaz
https://en.wikipedia.org/wiki/Federico_Aldrovandi
https://italychronicles.com/the-shocking-case-of-stefano-cuc...
...etc.
As in many other countries, the real problem is not guns (clarification: I'm against guns) but selection; someone letting his political views or the level of testosterone screw up his personal control during service should never ever be given an uniform, let alone a gun, period. And I'm 100% sure if we publicly screened every cop after service for drugs or steroids use, the scandal would explode within days. Cops are violent because corrupt powers need them as such: once they get a minor punishment or are acquitted after an unprovoked beating/killing, they can become a paramilitary force in the hands of the same politicians who helped them, both during service and after they retire. As usual, it's all about corruption.