Summary. It was Xerxes Hartfield's own companion who did it, and for no coin at all — he strangled the Colonel in the gun room within the half-hour after dinner, because the marriage the Colonel had spent a year contriving, and that day put a date to, meant the end of an arrangement of long standing that had never had a name to lose. Here is how I came to it.

The Reckoning. The method leaves little to argue over. Dr Quill, who does not love a mystery any more than I do, found the Colonel strangled by hand — no cord, no instrument, nothing composed or arranged about the body, which the household itself remarked was an ill-bred way to go. That plainness is itself a kind of signature. A man who stages nothing has generally done nothing but the deed. The window was shut and stiff with old paint; there is no other door; the only road to the gun room after Mrs Gow left the Colonel his coffee at 9:05, alive and the door standing ajar, was up the dining passage, and Mrs Gow stood at the foot of the service stair the whole twenty-five minutes and saw one man go up it. Not a woman — she was certain of that much, if the face was lost in the shadow — a man in evening dress, walking without hurry. That narrows the house considerably, and the house narrows itself further without my help.

Take the money first, since the household did. The unsigned settlement on the gun-room desk charges Nan's marriage portion against the Colonel's venture share, and looks, on its face, to profit half the table. But Nan sat in the drawing room with Lavinia and Fifi the whole half hour, unbroken, and in any case the settlement was unsigned and no will stands — the Colonel's death that night stops her allowance rather than freeing her, which is a poor motive for murder. Xerxes never left the dining table, vouched for three ways by Quill, Cousin R and Zane's serving, and besides had already given his word to the match a week before; killing the Colonel mends nothing he had not already resigned himself to. Effie was asleep in the morning room off the hall, not the passage, and her debts stood regardless, the Colonel having promised to settle nothing before Monday. Lavinia and Fifi were with Nan the whole time and had heard no threat that day to their weekly arrangements. Wat was in the kitchen passage under Mrs Gow's own eye, and had that afternoon been paid over generously — richer for the Colonel's life, not his death. Zane never left his serving, in the constant sight of three men. Cousin R sat over his port the whole half hour, and it is worth noting, in passing, that nothing about this killing bears his usual mark of arrangement; a man who collects secrets does not generally leave one lying strangled and untidy in a chair. Quill himself sat the whole time within arm's reach of two loaded pistols he never touched, which tells you something about the difference between a coroner and a killer.

That leaves the one man who left the table alone, was seen by no one for the whole window, and had a private passage running straight to the scene of it. Caught on the splintered chair arm was a single thread of dark crimson silk, and there is exactly one man in that house who wears such a sash, and wears nothing else of that colour, and has hands remarked upon in the kitchen for their strength from years of hauling cargo before ever he came to Cairnholm. Aziz has lived eleven years under Xerxes Hartfield's roof, unwaged and unnamed in any register the law or the drawing-room keeps — an attachment of long standing, of a kind the household did not discuss, and would not have thanked me for discussing either. The Colonel had argued a twelvemonth for the marriage that would give the venture a wife and a Cairnholm name, and that Sunday he put a date to it and made Xerxes drink the toast. He did not strike at Xerxes, who had already consented, nor at Nan, who was only made to stand and be thanked for a bargain not her own. He struck the man who had drawn the paper. It is not, I think, a mystery of money at all, whatever the settlement on the desk would have us read. It is grief, walking up a passage in evening dress with a coffee tray just gone by, and it is the third such matter I have closed this twelvemonth, by my count. Aziz is charged, and the file may close.

They'll whisper a fortnight the hand it was cold,
that Aziz was in it, the whole of it told.
And the Colonel, the colder, is carried the door,
and Cairnholm's acquaintance the fewer by four.
We'll vow to be watchful, we'll counsel more care —
and mean not a syllable, ever, we swear.