manny a non Catholic here - but I think this answers your question about not breaking the seal of confession.
the statement was made, not in the confessional booth, which the Church holds inviolate, but ‘as a friend’, that’s what they mean by ‘breaking the seal of confession’ (ie one done inside the confessional booth or in a formalized ‘forgive me Father for I have sinned’ manner)
The four people this man confessed to, by the way, appear to have been: 2 attorneys (one public defender, one not), this priest and his mom. I don’t think it comes up to the ‘blabbing around’ level, though.
The court also looked at the fact that the evidence against the guy in prison was pretty slim, one person, and that he’d had several eye witnesses to say he was elsewhere.
Re: the supplemental Hitchockian theme - At least for lawyers and therapists, my understanding is that they have an obligation to their client re: information about past activities, however, if they have information about future crimes, they have a ‘duty to warn’ in some sense.
not to transport this into another debate, but for me the scarier issue would have been ‘what if the kid had been sentenced to die’. And I don’t know what the Church’s position on that would be (since I’m neither Catholic nor do I play one on TV).