I know that under no circumstances can a priest break the secrecy of confession. I also know that according to the Catechism of the Catholic Church it is permissible to kill in self defense and especially in defense of others.
Take the purely hypothetical situation where someone tells the priest that he is going to poison the city’s water supply and kill the entire city. Should the priest break the secrecy of confession at that time and alter the authorities or not? If we have a grave responsibility
to protecting the lives of others including killing someone if necessary would this not fall under that category? To me it seems that it is the lesser sin to alert authorities in
defense of others than to kill someone in defense of others.