On the Eighth Day, the Seventh Commandment was what must be confessed.
『7 - "Thou shalt not commit adultery."』
Of course, because the sinner in question was already dead, this meant there was no action to be made on this day.
The Protagonist declared that the sinner who committed adultery was "Peter", the mother, but there was no way of knowing that for sure, and I also wouldn't simply trust her judgement on it when she's been accusing everyone of all sorts of things since the very beginning.
Either way, I knew for sure that whoever the cheater was, was dead.
Because, by the definition of 'adultery', one of the two parties involved must have been married, and there was, undoubtedly, no one who fit that description that remained.
Everyone still alive was younger than me, after all.
Thus, the Eighth Day continued without much consequence, albeit with a constant tense atmosphere.