"Not at the same time — but the fact that it's murder doesn't rule him out, according to Curnow. The police surgeon thinks he was killed quite a long time before the tide brought him to our notice."
"He wag drowned, though?"
"Oh, yes. No doubt about that. In a particular nasty fashion, my superintendent believes — he said that, from the marks and bruises they had found on the body, and from certain discolorations which occur after a drowning, he thought the poor chap had been hog-tied, hand and foot, and then held up by his ankles with his head and shoulders below the surface of the water. As you know, no amount of struggling overcomes that."
"How dreadful, Mark. Out at sea, I suppose?"
"Yes. They think he was probably lured aboard a boat on some pretext, overpowered when they were well out to sea, and then killed. If they'd fed him, bound, over the edge of a small boat head first, and then just held his ankles at the level of the gunwale, it wouldn't take more than a few minutes to drown him."
"It seems somewhat elaborate," she commented.
"Oh, I don't think there was any doubt that they had meant to make it appear like accident or suicide. He hadn't been hit on the head or drugged or anything — that's why they think he was lured aboard; either that or he knew and had no reason to suspect his killers... Whoever was holding the feet would simply have taken out a knife and sawn through the ankles bonds as soon as the struggles ceased, and then cut the ropes around the knees, and finally leaned over to sever the binding at the wrists — only it was further to lean, it was rough as you'll recall, and he muffed it."
"Is this just deduction, or is there —?"
"There's some evidence to prove it," Slate interrupted with a smile. "Curnow told me the rope around the wrists was half sawn through. The killer — or killers — must have been in too much of a hurry, that's all."
"And then they intended the tide to bring him ashore again in its own good time — minus bonds or marks of violence — to give the coroner another 'Accident' verdict."
"Exactly. Curnow inclines to the view that the murderers are what he calls foreigners. He says a local man would have known that, at this time of the year, the incoming tide would have brought him straight back on the next high. There's quite a rip, apparently, out beyond the headland there... and if they didn't mean the sea to keep him undiscovered for some appreciable time, then there would have been no point at all in going through the whole boat routine."
"Yes, that makes sense." April said slowly. "But I wonder why? What had the poor little man done?"
"He was an offensive and objectionable man — rather large, as a matter of fact."
"You and your fact! It's reasons that count, not facts. No, I mean I wonder if he was tied up with our killing, or whether it's just coincidence. I guess a second time makes a personal murder even less likely..."
They were sitting on a bench in the sideshow booth that had been Sheila Duncan's, trying to fit together the pieces of their particular jigsaw. Mark had spent the morning exploiting his newly-won friendship with Superintendent Curnow — and since they had both discovered the body, and had both had to make statements at the police station, it had seemed absurd to proceed any longer with the fiction that they did not know each other.
Accordingly, while they went over the affair in their minds, they had been investigating the booth's stock again, to see whether they might find some clue to what it was the mysterious burglar wanted.
"It has to be important," April said for the third time. "Otherwise people wouldn't be prepared to kill for it. It has to have an obvious and incriminating connection with Sheila's death. And at the same time, it must obviously be difficult to locate — otherwise three separate burglaries, all of them so far as we know unsuccessful, would not have been necessary."
"Do you think he'll try again?" Slate asked.
"I don't see how he could... not with the risk there'd be."
"So for once we're in a good position to get a move ahead of the game, as it were."
"We're in a good position to try. Oh — and I forgot one other factor in my list of things our unidentified object has to satisfy. It must be something to which a request for a black Porphyry pixie, a non-existent pixie, can be a lead!"
Mark ran his fingers through his short hair. "And it's all here, ladies and gentlemen," he said oracularly. "All the stock the lady possessed laid out in neat and orderly rows on counter and chair and desk and drawer and floor for your distinguished inspection! Walk up, walk up, and take a look! Take your pick — take your shovel, if you so wish — and examine carefully every single one. These are the clues — all you have to do is to interpret them to win a big money prize!"
"And not a Porphyry pixie amongst them!" the girl said sepulchrally. "Either in black or in any other — Hey! Wait a minute, though... There are no Porphyry pixies, but there are a few Porphyry lighthouses. Black ones, too! Look, at the back there, behind the ashtrays you stood on that drawer. Where did you find that little haul, by the way? I didn't put it there."
"The ashtrays were in a cardboard box that the dustbin was standing on. I think they must just have been delivered, all the same: they were still wrapped in tissue... The lighthouses — they're only about three inches high, as you see — the light houses were inside those tall white mugs standing on the shelf above the sink there. Come to think of it, that's an odd place to put stock when you still have shelf room to spare, and…"
His voice tailed away. They looked at each other.
The girl moved first. Snatching up one of the miniature stone models, she began turning it over and over in her hands. "That's all there were?" she asked absently. "Just the seven?"
"That's all I've found," Slate said. He picked up one of the black lighthouses himself and examined it. "I've never really looked at them before," he went on. "I know they turn them up on a lathe and then polish them with a carborundum wheel, and I suppose they have something like a potter's wheel for the round boxes and ashtrays.
"I was just thinking," the agent said slowly. "Lighthouses are peculiarly suitable for shaping on a lathe: from whichever point of the compass you look at them, the shape of the elevation is always the same. And the plan is simply a decreasing or increasing circle."
"So?"
"So you'd expect to find, at the top and bottom, a tiny mark, a trace of the hole into which the spindle of the lathe fitted, even if it had been subsequently filled up — Look, you can see it on these Serpentine ones, the big and the small... Here and here... and here, too. But not a sign on the black ones."
"And that implies?"
"I should say it meant that these particular lighthouses had been made in two separate sections and then screwed together. The parts where the lathe spindle had fitted would be hidden within the join, then."
"You're right! Yes, you're' right," April said excitedly. "You can see the join where the wide curve of the base flattens out to make the main tower of the lighthouse. And I think... yes... I think it will be quite... easy... Ah! There we are!... to unscrew!" She held up the two halves of the stone souvenir.
There was a shallow depression in the base, threaded to take the complementary extension projecting from the top half.
But the projection from the top half was itself hollow: inside the threaded collar, a recess two inches deep and about the diameter of a fountain pen was tunnelled up into the shaft of the lighthouse.