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,
