“You see now how I was beginning to look at the affair. But I was considerably worried by the woman with the neat shoe. Her part in the business would have to be cleared up eventually; but for the moment I had to put it aside.
“And then our friends made their second blunder—trying to prove too much, as usual. Friend Cargill came on the scene, innocently going down to bathe. He sat down on the groyne and proceeded to dig up a .38 cartridge-case, which he presented to me like an honest fellow anxious only to help the police. Well, all three of us had been over that particular bit of sand and had seen no cartridge-case before he arrived on the scene. Also, as I pointed out to you, squire, an automatic ejects its cartridge-case sharply and jerks it well behind you, especially on hard sand where the thing can jump along. It was obvious that no one could fire a shot from Fleetwood's position at the groyne and leave his ejected shell lying close under the groyne, where Cargill assured me he'd kicked it up. So naturally I began to look at Mr. Cargill with more than common interest; and, as you saw yourselves, he's got a build rather like the claimant's, so I wondered if they were related.
“Then our friend Cargill told us his yarn about meeting Derek Fordingbridge in the war; and off he went to meet his dear old friend. And later on he volunteered eagerly that he'd had a talk with the dear old fellow. By that time I was more than a bit suspicious of the dear old friend; and naturally some of that suspicion spilled over on to Cargill. If the claimant was an impostor, then the man who recognised him was a liar; and, as I had no use for aimless liars in a case of this sort, I inferred that Master Cargill was one of the gang, posted at the hotel for intelligence purposes—to keep an eye on the Fordingbridge group. And that cleared up one of the main difficulties I'd had—namely, how the murderer had known to use a .38 automatic so as to match the Fleetwood pistol. Of course, if you assume that Cargill had taken the opportunity of rummaging in Fleetwood's room, or had drawn him into talk about pistols, they would be sure of their ground on that point. That had been a troublesome point to me; for I didn't like to stretch coincidence to the extent of assuming it was mere accident that made the Fleetwood pistol and the bullet in the body both of the same calibre.
“It remained to check Billingford's story as far as possible, and you know how the runnel helped us in that. What the facts of the case proved beyond any reasonable doubt was that at 11.19 p.m. Billingford was about three-quarters of a mile from Neptune's Seat. With the sound of the sea in his ears, it's most unlikely that he could hear a pistol-shot at that distance. And his tracks showed him walking along quite steadily there. Then, at a point far nearer the rock—a point that I suppose he may have reached about 11.35 p.m.—the trail showed that he began to run. Now that fitted in with his story. At that second point he might quite well have heard a shot fired on the rock, just as he said he did. He couldn't possibly, on the facts we established, have reached the rock before about 11.37 or 11.38; and by that time the murder was done and the murderer had got away.
“By that time I felt fairly sure of my ground; and I got that digging in the sand started, just on the off-chance that we might get hold of the shell of the cartridge which really did kill Staveley. It wasn't absolutely necessary for the case; but, if it turned up, then it would help to confirm my notions. As it was bound to be below tide-mark, there was no point in trying to locate its exact position, since it might have been washed about by the waves in the falling tide after the shot was fired. So I simply had the whole strip of sand dug up and dumped down above the high-water mark for future examination.
“Meanwhile, I'd been on the hunt for the dame with the neat shoe—a No. 4, as you remember. There were several of the guests wearing shoes of that size; but I picked out Mme. Laurent-Desrousseaux first of all because she seemed likeliest. Staveley had served in France; she was a Frenchwoman; she was at Lynden Sands Hotel, where she most obviously was out of place and knew no one. It seemed best to find out something about her.
“I talked to her. She was a bit lonely, it seems, and quite ready to go for a walk now and again. I know my own length of pace; so, by counting hers in a given distance and comparing with the numbers of my own, I made a fair guess at her step-measurement. It fitted in with the prints of the neat shoe on the sands. Gentle treatment did the rest, as you saw. She told us her story quite honestly, and it threw a good deal of light on the affair. I inferred from it just what you yourself inferred later on, squire: the shot fired by Mrs. Fleetwood at 11.19; Staveley's fall on the rock; and the bolt in the car to the hotel. And, in turn, this checked Billingford's story quite neatly, because he couldn't have heard the shot at 11.19, being so far away. It was the second shot, about 11.35, that he heard.
“Now, let's reconstruct what really happened; and remember that, although it was full moon, it was a cloudy night, and the light was bad all through. We'll begin with Staveley leaving the cottage. He's in a bad temper; been drinking as well as playing poker. He gets to the rock and waits for Mme. Laurent-Desrousseaux. She's late; and his temper gets worse. She arrives and tells him she wants to get a divorce arranged. Between his temper and the chance he sees of making her pay sweetly for the favour she asks he treats her brutally, and sends her off both pained and angry. Then Mrs. Fleetwood arrives, and that meeting culminates in the shot she fired at 11.19 by accident. Then you get the talk between the Fleetwoods at the car, overheard by Mme. Laurent-Desrousseaux; their drive back to the hotel; and her hurry to get away from what she thinks is the scene of a murder. That leaves Staveley on the rock, stunned by his fall; and Billingford sauntering across the sands towards the runnel. In the meantime, Aird and the gentleman without a face have got out the boat belonging to Flatt's cottage and are rowing for Neptune's Seat, which is just above tide-level.
“Down comes the rain. Staveley gets soaked; and perhaps the chill revives him. He staggers up and puts on his rainproof. Then in comes the boat, and they shoot him without having to land on the rock at all. The ejector jerks the cartridge-case into the water, where it sinks into the sand and gets covered up by the wash of the waves. The murderer and his pal row off into the dark. Meanwhile Billingford has heard the shot, and he, not knowing anything about this little plot, rushes up—rather pluckily—to see what it's all about, and he finds the body on the rock. That explains the two shots and the general chronology of the affair.
“Now, by this time friend Cargill had made his second error. He'd been keeping his eye on things at the hotel, and he'd got hold of that envelope which Mme. Laurent-Desrousseaux addressed to Staveley and dropped in the waste-paper basket. He thought he could give me a fresh scent to follow up, and he was just going to produce it when he realised that Mme. Laurent-Desrousseaux herself was with us; so he suppressed it then and handed it over later on. All it did was to confirm me in the idea that he was one of the gang.