The inspector finished his writing, and then regarded Cayley thoughtfully. Suddenly he said:

“What is your theory of Robert’s death?”

Cayley shrugged his shoulders.

“You’ve probably seen more than I’ve seen,” he answered. “It’s your job. I can only speak as a layman⁠—and Mark’s friend.”

“Well?”

“Then I should say that Robert came here meaning trouble, and bringing a revolver with him. He produced it almost at once, Mark tried to get it from him, there was a little struggle perhaps, and it went off. Mark lost his head, finding himself there with a revolver in his hand and a dead man at his feet. His one idea was to escape. He locked the door almost instinctively, and then, when he heard me hammering at it, went out of the window.”