Summary. It was the Colonel, and for no cause stranger than a master's pride in a servant kept too long above himself; here is how I came to it.

The Reckoning. Zane died in the gun-room passage at about a quarter past nine, shot once at close range with one of the Colonel's own Sunday pistols, and the pistol's fellow left sitting in a case whose lid had been split by a hard blow against the wall. That violence to good rosewood, and the bent candlestick found on the gun-room threshold, are not a thief's marks nor a stranger's — they are the marks of a man moving fast and blind in the dark, wrenching at a thing he knows by feel because he has owned it thirty years. The broken lantern slide underfoot, ground to nothing under a heel, tells the same tale from the other end of the passage: someone left the lantern table in the dark and came back to it in a hurry, without troubling to see what he trod on. Only one person in that room had cause to leave his chair, and only one person's chair Nan Pringle found gone cold beneath her hand. She had him back beside her by twenty past nine, breathing like a man who had been at something.

The rest of the household falls away easily enough, and I set it down chiefly for the file's sake. Lavinia never left her chair; Dr Quill and Mrs Gow both had her in view the whole twenty minutes, and the shot came before she could have crossed the hall. Cousin R had his hands full at the lantern table throughout, by the Colonel's own word and Nan's, and a man cannot be feeding slides and firing pistols in the same breath. Quill sat with his glass in plain sight of two witnesses and was sent for only after the body was found, which clears a man as neatly as anything can. Nan herself was seated the whole while, and it is her own cold report of the empty chair that points the finger elsewhere than at her. Aziz had been in that passage at five past nine, true enough, but Mrs Gow met him coming back with the umbrella and had him under her eye in the drawing-room a full ten minutes before the shot; besides which he had never laid eyes on Zane before that evening and had to ask which twin he was — no motive grows that quick. Fifi was belowstairs with Mrs Gow the whole time, and came up the servants' stair with her when the shot was heard.

The lavender in Zane's buttonhole was the beginning and end of the Colonel's fury, though he'd have called it something grander at the time — a matter of what is owed a house, and who forgets it. Word had reached him that afternoon, carried up by a boot-boy who ought to have kept his mouth shut, that Zane had been seen coming down from Lady Lavinia's room in his shirtsleeves. Eleven years the Colonel had held that footman up as the very model of a servant who knows his place, and dined that night unable to speak of anything else. It was not love lost, nor money owed, that took a man into a dark passage with a loaded pistol; it was a whole creed of who stands where, broken under his own roof by a servant he had trusted past the ordinary trusting of servants. He struck the case open, took a pistol, and put an end to what he could not otherwise unsay. I have charged Colonel Cecil Cruikshank accordingly. The third this twelvemonth, by my count, and I don't doubt Cairnholm will find me a fourth before the year is properly out.

They'll whisper a fortnight the hand it was cold,
that the Colonel was in it, the whole of it told.
And Zane, 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.