I left them for a little to form their own estimates. For the most part they looked neither sick nor revolted: their reactions were mainly of shock and minds still consciously fighting against comprehension. No glances were exchanged, no eyes moved: their eyes were only for me.

Stryker had a split upper lip, a tooth missing, and a reddish rough mark on his temple which I think must have been caused by another stone very probably all the injuries were inflicted in this fashion to avoid any telltale marking of the hands or knuckles. Had those injuries been sustained in the course of a fight there would have been extensive bleeding and fairly massive bruising: there were no signs of either because Stryker was dead and circulation had ceased before those wounds were caused. To complete what he thought would be a most convincing effect, the murderer then closed the dead man's hand round one of the buttons torn from Allen's coat. Incidentally, there were no signs whatever of the churned up snow one would have expected to find at the scene of a fight: there were two sets of tracks leading to the place where Stryker lay, one set leading away. No fuss, no commotion, just a quick if not particularly clean dispatch." I sipped some more of Otto's Scotch-it must have come from his own private supply for it was excellent stuff-then asked in my best lecturer's fashion: "Are there any questions?"

Predictably, there were none. They were all clearly far too busy asking themselves questions to have any time to put any to me. I went on: "I think you'd agree, then, that it now seems extremely improbable that any of the four previous deaths were the results of innocent Coincidence. I think that only the most gullible and the most navve would now be prepared to believe that those deaths were unconnected and not the work of the same agent. So what we have is, in effect, a mass murderer.

A man who is either mad, a pathological killer, or a vicious and evil monster who finds it essential to murder with what can be only an apparent indiscrimination in order to achieve God knows what murky ends. He may, it is possible, be all three of those at once. Whatever he is or whoever he is, he's in this cabin now. I wonder which one of you it is?"

For the first time their eyes left me as they looked quickly and furtively at one another as if in the ludicrous hope that they might by this means discover the identity of the killer. None of them examined one another as closely as I observed them all over the rim of my glass, if one pair of eyes remained fixed on mine it could only be because its owner knew who the murderer was and didn't have to bother to look around: but I knew, even as I watched them, that I had no real foundation for any such hope, the murderer may have been no great shakes at physiology but he was far too clever to walk into what, for an intelligent man with five deaths on his conscience, must have been a very obvious trap indeed. I was certain that there wasn't a pair of eyes before me that didn't flicker surreptitiously around the cabin. I waited patiently until I had their combined attention again.

I have no idea who this murderous fiend may be," I said, "but I think I can with certainty say who it isn't. Counting the absent Miss Haynes, there are twenty-two of us in this cabin: to nine of those I cannot see that any suspicion can possibly attach."

"Merciful God!" Goin muttered. "Merciful God! This is monstrous, Dr. Marlowe, unbelievable. One of us here, one of the people we know, one of our friends has the blood of five people on his hands? It can't be!

It just can't be!"

"Except that you know that it must be," I said. Goin made no reply. "To begin with, I myself am in the clear, not because I know I am-we could all claim that-but because two hostile acts have been committed against my person, one of which was intended to be lethal. Further, I was bringing in Mr. Smith here when Stryker was killed and Allen injured." This last was the truth but not the whole truth but only the killer himself would know that and as he was already on to me his opinion was unimportant because he couldn't possibly voice it. "Mr. Smith is in the clear because not only was he unconscious at the time, he was a nearly fatal victim of the poisoner's activities and its hardly likely that he would go around poisoning himself."

"Then that lets me out, Dr. Marlowe!" The Duke's voice was a cracked falsetto, hoarse with strain. It wasn't me, it couldn't-"

"Agreed, Cecil, it wasn't you. Apart from the fact that you were another poisoning victim I don't think-well, I'm not being physically disparaging but I'd think it very unlikely that you could have hoisted that rock that was used to kill Stryker. Mr. Gerran, too, is above suspicion: not only was he poisoned but he was in the cabin here at the time of Stryker's death. Allen obviously, could have had nothing to do with it and neither did Mr. Goin here, although you'll have to take my word for that."

"What does that mean, Dr. Marlowe?" Goin's voice was steady.

"Because when you first saw Stryker's body you turned as white as the proverbial sheet. People can do lots of things with their bodies but they can't switch on and off the epidermal blood supply at will. Had you been prepared for the sight you saw you wouldn't have changed colour. You did. So you weren't prepared. Our two Marys here we'll have to leave out of the reckoning for it would have been a physical impossibility for either of them to have attacked Stryker with that rock. And Miss Haynes, of course, doesn't come into the reckoning at all. Which, by my count, leaves thirteen potential suspects in all." I looked round the cabin and counted.

"That's right. Thirteen. Let's hope it's going to be a very unlucky number for one of you."

"Dr. Marlowe," Goin said. I think you should consider withdrawing your resignation.

"Consider it withdrawn. I was beginning to wonder what I'd do for food anyway." I looked at my now empty glass then at Otto. "Seeing that I'm now back on the strength, as it were, would it be in order-"

"Of course, of course." Otto, looking stricken, sunk heavily onto a providentially sturdy stool and insofar as it was possible for over two hundred weights of lard to look like a punctured balloon, he looked like a punctured balloon. "Dear God, this is ghastly. One of us here is a murderer. One of us here has killed five people!" He shivered violently although the temperature had by this time risen well above freezing point. "Five people. Dead. And the man who did it is here!"

I lit a cigarette, sipped a little more of Otto's Scotch and waited for some further contributions to the conversation. Outside, the wind had strengthened until it was now a high and lonesome moaning sound that set the teeth on edge, a moan that regularly climbed up the register into a weird and eldritch whistling as the wind gusted and fell away: everyone appeared to be listening to it and listening intently, a weirdly appropriate litany for the fear and the horror that was closing in on their minds, a fit requiem for the dead Stryker. A whole minute dragged by and no one spoke so I took up the conversational burden again.

"The implications will not have escaped you," I said. "At least, when you have had as much time to think about them as I've had, they won't.

Stryker is dead-and so are four others. Who should want them dead? Why should they have dieX Is there a reason, a purpose behind those slayings? Have we a psychopathic murderer amongst us? If there is a purpose, has it been achieved:" If it hasn't-or if the killer is a psychopath-which one of us is going to be next? Who is going to die tonight?

Who is going to go to his cubicle tonight knowing that anyone, a crazed killer, it may be, is going to enter at any time-or even, possibly one's own roommate may be waiting his turn with a knife or a suffocating pillow?