“I have, indeed,” replied Mr. Ludgrove gravely. “The papers contain little beyond the bare facts, but I gather that this unfortunate Mr. Martin was undoubtedly murdered?”

“I’m afraid so,” replied the Inspector. “And I fancy by the same hand which committed the previous murders. We found a typed letter on him, suggesting that he should call at Number 407, which had been posted in this district, and there was a counter bearing the number IV lying by his side. You don’t happen to know anything about this Mr. Martin, I suppose?”