“But, at the last when it was too late, when they got down to the subject of cold cash, his business sense flashed a red light. He wanted to send down a disinterested diver — not Floyd, as was immediately suggested — for a preliminary survey. He wanted some really tangible evidence. Linda, seeing his hesitation, held out, too.
“Something had to be done at once. They did it. They stalled him off until they could plant some evidence. They stole the Hussar relics and placed an order for the counterfeit guineas. They were so close to $200,000 that their mouths watered; and, if Ira’s pretty-looking blueprints and his model suction salvage apparatus weren’t enough in the way of confidence-game props, they’d supply what was.
“And now — because of a certain motive which will be discussed shortly — the murderer went into action.
“He knew that Ira was a fake expert, and he knew that Floyd was going to dive and salt the site of the wreck. He typed the diving chart. The method wasn’t sure fire, of course. Either Floyd or Ira might possibly suspect the chart — but he took that chance rather than resort to any first-hand and possibly bloody murder method; He couldn’t bring himself to that. Even if the chart was noticed, Floyd could only suspect Brooke or Rappourt — which would be all right, too. One of his motives was to smash the con-game. If the conspirators quarreled — that was fine. He might not even have to murder.
“While, if it did work — as it did — Brooke would find himself in a spot. That would be another monkey wrench in the swindle machinery — Brooke, fearing exposure, because of Floyd’s death while diving, could be expected to take it on the lam. But, as it happens, Brooke doesn’t scare easily. He is a professional and knows his job. He promptly put his customary con-man’s ingenuity to work. Floyd had gone in to New York, before diving, to get the relics from Ira’s room and to make it appear he wasn’t on the island. He went in again, afterward, in order to shuck the heavy underwear necessary for diving at that depth and to return legitimately via the water taxi. But when he failed to come back, Ira began to worry and sneaked in to check up. He found Floyd dead in the hotel room. That wouldn’t do at all. He had to think fast. He moved the body, took some very clever and direct steps to prevent any immediate identification, and then, later, some others to prevent any suspicion that Floyd, though missing, wasn’t in perfectly good health. He wrote the letter, and posted it by what we might call the boomerang method.”
Merlini crushed his cigarette in an ash tray. Sigrid and Gail were listening intently. Gavigan watched them, but he paid attention. I got up and added ice to my drink. Burt, following me, poured himself another brandy.
“Do you remember what that letter said?” Merlini asked. “ ‘Kick in before I get back, or else.’ Brooke and Rappourt were, in the face of imminent disaster, making a last stand, trying to push the con-game to its pay-off before the dead Floyd could appear to embarrass them. They were playing for time until Lamb had completed his independent diving survey and been convinced by the relics Floyd had planted. The guineas would have been there, too, except that Lamb, having rushed matters, had made Floyd’s dive necessary before the counterfeiter had delivered them.
“Brooke and Rappourt, you might note, are at this point eliminated as suspects in Linda’s murder — they’d hardly kill one of the geese that were about to lay the golden eggs. They’re innocent on another count, also. Had they intended to murder Linda later, they’d have taken more care with the letter-mailing details. They never expected an official investigation or they’d have not used the typewriter they did, or left the faintest smudge of a fingerprint on the notepaper, or planted it on a train that took such a roundabout route to Chicago. They could hardly have expected to cover up Floyd’s death successfully. They’d have known that a missing person—”
“Skip it,” Gavigan said. “I’m damned if I’ll listen to all the hair-splitting logic that proves innocence in Linda’s death when Rappourt was the intended victim.”
“As you say, Inspector. And we’ll skip the logic that proves Rappourt and Brooke were innocent in plotting Rappourt’s death. It should be obvious—” Merlini’s eyes twinkled impishly—“though there are one or two other things I should have thought were obvious, too. Perhaps I had better—”
“Go ahead, gloat! But if you don’t get to the point soon, I’m going to arrest you as an accessory after the fact. Why are you so damned sure there’s only one murderer? Why couldn’t there be two — one for Floyd and one for Rappourt?” Gavigan eyed Sigrid and Gail almost hungrily.
“No,” Merlini protested. “Not two. I won’t have it. That would give us one potential murderer and three actual ones out of only seven suspects. The percentage is absurd. Not only that, but the essential similarity of means — two finicky long-range murder methods: the poison and the typewriter — is indicative of one and the same person.
“Floyd’s murder was nearly perfect. All the murderer did was type a few words on a sheet of paper and tack it up at the houseboat. The only really solid deduction we can draw from the whole business is that the murderer knew Ira was a phony. As for the first attempt on Rappourt, the murderer simply substituted cyanide for the contents of the top capsule in the vial. Another small action much easier than the bloody businesses of shooting and head bashing.
“Then Rappourt perversely gave the capsule to Linda. The first crime was brilliant; the second a miserable piece of amateur bungling. And yet, in spite of it — the murderer’s luck held — he was still as safe as houses. Rappourt didn’t know the finger had been put on her, and there was no motive the murderer could possibly be suspected of having for Linda’s murder. But one thing bothered him. When he discovered how his plan had misfired, he didn’t know when Linda had died nor whether he had an alibi. That worried him enough so that he cooked up his first piece of misdirection — the fire. The fire, the evidence of the murderer who knew too much, and the bullet that traveled in a curve. Those three things separately and together solve the case and name the culprit.”
Merlini leaned forward and picked his glass from the floor. “When we found that no one had the slightest opportunity to set the fire, I thought it looked suspiciously like a manufactured alibi, an act for the special benefit of Ross and myself. Now, if that was true, it indicated someone who knew we’d be where we were when we were, someone who knew we were coming to the island last night—”
“Both Miss Verrill and Dr. Gail—” Gavigan began.
“Yes. Also Arnold. But, if you remember, I hadn’t told Sigrid we would land at the haunted house. She and those other two expected me at the séance. That was all they knew. But the murderer—” Merlini stopped exasperatingly and raised his glass to his lips at last, as if to drink. I knew then that he was playing catlike with the murderer, tantalizing, taunting him, pretending to drink and hoping — for what?