“Ah!” said Randall. “That was certainly a mistake on my part.” He walked across the room to his desk, and picked up the evening paper that lay there, and came slowly back with it. “I think that's the most important part of my story—as far as you are concerned,” he said, and handed the paper to Hannasyde. “The second paragraph,” he said.

Hannasyde shot one quick look at him, and then lowered his gaze to the column just below the fold in the newspaper.

Accident on the Piccadilly Tube was the heading. Underneath was a brief statement that shortly after three o'clock in the afternoon a middle-aged man threw himself in front of an express train at Hyde Park Corner Station. It was understood that the man was a Mr Edward Rumbold, of Holly Lodge, Grinley Heath, well-known in City circles as the head of a firm of wool-exporters.

Hannasyde read it deliberately through, and then laid down the paper. “I think you have a good deal to explain to me, Mr Matthews,” he said sternly. “What am I to understand by this?”

Randall finished his brandy, and set the glass down on the mantelpiece behind him. “Well, there won't be a case, Superintendent,” he answered.

“He murdered your uncle?”

“Incredible, isn't it?” said Randall. “But quite true. Only I think we won't call it murder. My uncle had been blackmailing him for years.”

“Then your uncle was John Hyde?” Hannasyde said swiftly.

“Yes, he was. But you'd already guessed that, I think. I hope you appreciate his choice of pseudonym. He had a pretty sense of humour, hadn't he?”

“How long have you known this?” demanded Hannasyde.