Summary. It was Effie Strange, and for the sapphire, not for love nor money owed alone; here is how I came to it.

The Reckoning. She had wanted the stone for a long while, in the way of a girl who has already spent, in her head, money she has never held. Three hundred and twelve pounds she owed about the town, and Friday last her chemist had shut his book to her. Saturday she asked Xerxes outright for a loan, in the library, and was told no, twice, pleasantly, by a footman's account. That same Saturday, at the tea table, she heard him tell the Colonel that the loose sapphire and Aziz's stone besides were going under lock that week, off to Struan the jeweller and out of any hand's easy reach. The theft she had been counting on, whenever the opportunity came ripe, was being shut away by the one man standing between her and it. She did not wait for the opportunity. She made one.

The method wants no more staging than the house allowed. Dr Quill's phial sat unwatched in the hall from eight o'clock, and three people said as much at once; anyone crossing might have lifted it, and she did. Xerxes's glass was poured at the table at 9:10, in full view, and he carried it himself into the blue sitting room at quarter past — so the wine left that room clean, and whatever went into it went in after. Effie rose at 9:20 for air. She did not take the air in the garden and come back wet by chance; she went out the front, round to the unbolted garden door, and up the back passage to the still-room, which a man may reach from the garden without troubling the dining room at all. There she took Mabel's cut meat off the shelf — a small mercy to a great cat, and a useful one, to keep the beast fed and lying still — and through the passage door, unseen from the dining room, put the laudanum into his glass while he dozed over it. She waited for it to take hold, as a body must; and when he was insensible she finished the business with the settle's own cushion, which needed no bringing and left no mark of struggle, only fringe-threads at a dead man's mouth. The phial she left empty on the still-room shelf. She went out again by the garden door and came in the front at 9:50, her hair still wet, though the rain itself had stopped at eight — the one detail that would not sit quiet, and very near the one I nearly overlooked, since a damp head means a garden visited after the sky had already dried, and there is only the one door that explains it.

She did not get the stone. Aziz never left the company that mattered — dining room till 9:40, then the front hall with Lavinia unbroken till the body was found — and his sapphire was still at his throat when they found the body. The loose stone from the desk slip-case was never on her person that anyone saw, and I do not think she reached it before Gaunt's knock at ten sent the house into its fright. She meant a theft and got only a corpse for her trouble, which is its own kind of justice, though not the kind I am paid to admire.

The rest of the table falls away easily enough. The Colonel and Nan sat together in six people's sight from nine until the finding, neither stirring; the dosing came after 9:15, in the sitting room, and neither was ever near it. Wat had left the table at 9:05, before the glass was even poured, and the tide-clerk at Kirk Wynd steps had him aboard the Merle at 9:35 and ashore at 10:20 — off the premises the whole while, and besides due to be paid out of the dead man's cargo, which argues against rather than for him. Cousin R never left the cards, witnessed the whole two hours through. Lavinia had no unwatched interval at all, being with Aziz from 9:40 straight through to the discovery. Gaunt's single absence was under two minutes at a shut door he did not open — too short by far for a dose to take its slow effect. And Quill, whose phial it was, sat at the table till ten and then in the billiard room with the Colonel; the case may have stood open to any hand in the hall, but only one of those hands can be placed in the still-room, and it was not his.

Effie alone was unaccounted for the whole of the window, 9:20 to 9:50, and came back from her "air" with water on her that the weather does not explain. I have charged her with the wilful murder of Xerxes Hartfield, done for the sake of a jewel she could not bear to see locked from her. The third such matter to cross my desk this twelvemonth, by my count, and I do not expect it to be the last out of that house.

Effie slipped out through the garden with a heart of stone,
While Xerxes in the blue room sat alone,
The phial's bitter draught in wine was poured,
The back-passage door left just untoward,
She waited till his breathing came no more—
The laudanum, the cushion, and the floor.