“H’m,” said the inspector. “Man found an open window. Climbed in, saw Mr. Ackroyd sitting there⁠—maybe he’d fallen asleep. Man stabbed him from behind, then lost his nerve and made off. But he’s left his tracks pretty clearly. We ought to get hold of him without much difficulty. No suspicious strangers been hanging about anywhere?”

“Oh!” I said suddenly.

“What is it, doctor?”

“I met a man this evening⁠—just as I was turning out of the gate. He asked me the way to Fernly Park.”

“What time would that be?”

“Just nine o’clock. I heard it chime the hour as I was turning out of the gate.”

“Can you describe him?”