u/AMusicianOfSomekind

Hi there, non catholic here. I was wandering what a priest would do if someone confessed to murder or confessed intent to carry out a murder in the seal of confession. Im aware that breaking the seal of confession is a major no no but if someone confessed to doing something do serious or confessed they planned to do it and then acted on it and a priest already knew without intervening, would it not be a sin to knowingly not protect innocent people with the knowledge that it could have been prevented?