Summary. It was Simeon Gaunt, her own half-brother and the trustee of her money, and he did it to stop the ten o'clock sitting before it could call up their mother's name in his own ledger of sins; here is how I came to it.

The Reckoning. The passage told the first part plainly enough. Nothing had been taken, nothing arranged, nothing posed — a death done in haste and in anger, not in design. The trust papers scattered beside her, stamped three times over with Gaunt's own hand as trustee, and the card in the conservatory with Isolde Marsh's name writ at its head, told the rest. Lavinia was born a Marsh, as he was born a Gaunt, sharing one mother between them; she had gone to the séance table under the name, and meant that night to call their mother up by her Christian name before the whole house and speak of debts long unpaid. That is an imposture a clergyman of his habit calls the robbing of a soul, and he had said so from the pulpit not a month before. It was also, more to the point of his own comfort, to be paid for out of money he administered and had failed three times over to stop, the solicitors' letter of that very evening confirming as much. A man may preach against necromancy for a fortnight and feel nothing; set it against his own blood and his own purse, and against a lifetime of being the dutiful son to her the favoured, less dutiful one, and the preaching turns to something with hands in it.

The method bears this out better than any confession. Dr Quill found no instrument used — bare hands, and a beating continued past any need of it, which speaks to rage worked loose rather than a plan carried out. Gaunt's own signature, when he corrects the erring, is the cord and the staged penance, the tableau the household would know for his; none of that is in the passage. This was not judgment administered in his usual coin. It was a man who had told himself for thirty years that his anger was righteousness, finding at last an hour when he no longer troubled to separate the two. He left the dining room before nine, by the only way left open to him on account of the repotting, and came back at twenty minutes to ten with his knuckles grazed and a ready word about a tub in the dark — a story he never altered, because he had, I think, already filed it in his own mind as providence rather than crime.

The others fall away on plainer ground. Zane was setting chairs in the conservatory from a quarter to nine under two gardeners' eyes that never left him, whatever else had passed between himself and the dead woman on three earlier evenings. Wat was on the terrace disputing freight with Xerxes from ten minutes to nine, seen throughout by Aziz and the gardeners both, and in any case she had refused him his two hundred pounds and nothing of hers was taken — a debt uncollected teaches a blackmailer patience, not murder. Cousin R and Effie Strange held each other's alibi in the library from half past eight, under the footman's eye, and besides, a man of R's habits does not leave a scene so entirely without composition, nor does Effie owe a debt that was ever asked for — Lavinia's forty pounds to her went unclaimed to the end.

I had near forgotten the one small thing that closes it. Gaunt told me himself, unprompted, that he struck his hand against a tub in the passage dark — and told it the same way twice, word for word, the way a man recites a thing he has already decided to believe. The dead do not care for our reasons. I have charged him, and that is the third this twelvemonth, by my count, and the year not done.

Gaunt hid among tubs where the draughts were chill,
And Lavinia entered with flowers to fill.
No cord and no scourge adorned the affair,
While tea was arranged with particular care.
The lesson is clear, if a lesson be sought:
Do not strike your kin—unless greatly distraught.