Dear god.. that must be incredibly traumatising for people. Imagine the fear the people must have had during that time being held hostage or when they were in the arms of the rioters. That is honestly terrifying. Really feel for them and thoughts go out to their families.
That just sounds crazy. I've heard that Brazilian jails are meant to be among the most brutal in the world, but decapitation is taking it to another level. That's one place you do not want to get into trouble!