ng more. Perhaps it wasn't a pistol-shot after all. After a
moment or two he goes to the library door again. The profound silence
makes him uneasy now. Was it a pistol-shot? Absurd! Still--no harm in
going into the office on some excuse, just to reassure himself. So he
tries the door--and finds it locked!

What are his emotions now? Alarm, uncertainty. Something is happening.
Incredible though it seems, it must have been a pistol-shot. He is
banging at the door and calling out to Mark, and there is no answer.
Alarm--yes. But alarm for whose safety? Mark's, obviously. Robert is a
stranger; Mark is an intimate friend. Robert has written a letter that
morning, the letter of a man in a dangerous temper. Robert is the tough
customer; Mark the highly civilized gentleman. If there has been a
quarrel, it is Robert who has shot Mark. He bangs at the door again.

Of course, to Antony, coming suddenly upon this scene, Cayley's conduct
had seemed rather absurd, but then, just for the moment, Cayley had lost
his head. Anybody else might have done the same. But, as soon as Antony
suggested trying the windows, Cayley saw that that was the obvious thing
to do. So he leads the way to the windows--the longest way.

Why? To give the murderer time to escape? If he had thought then that
Mark was the murderer, perhaps, yes. But he thinks that Robert is the
murderer. If he is not hiding anything, he must think so. Indeed he says
so, when he sees the body; "I was afraid it was Mark," he says, when he
finds that it is Robert who is killed. No reason, then, for wishing to
gain time. On the contrary, every instinct would urge him to get into
the room as quickly as possible, and seize the wicked Robert. Yet he
goes the longest way round. Why? And then, why run?

"That's the question," said Antony to himself, as he filled his pipe,
"and bless me if I know the answer. It may be, of course, that Cayley is
just a coward. He was in no hurry to get close to Robert's revolver, and
yet wanted me to think that he was bursting with eagerness. That would
explain it, but then that makes Cayley out a coward. Is he? At any rate
he pushed his face up against the window bravely enough. No, I want a
better answer than that."

He sat there with his unlit pipe in his hand, thinking. There were one
or two other things in the back of his brain, waiting to be taken out
and looked at. For the moment he left them undisturbed. They would come
back to him later when he