Frant was so astonished by the inspector’s uncharacteristic indifference to his meal-times, which he felt must portend some occurrence of great importance, that the news he had come hot-foot to tell seemed in comparison a minor matter. But as he told his story something of his earlier enthusiasm returned, and the obvious interest with which Mallett listened gave him additional encouragement.

“I went straight to Renshaw after leaving you,” he began, “and he gave me a free hand with all Ballantine’s papers. There was nothing at all to be found among the private documents that helped me in the least. There were very few private documents of any kind, for the matter of that.”

“I’m not surprised,” commented Mallett. “For one reason or another, Ballantine took care to leave very little in the way of personal papers behind him.”

“Then it occurred to me,” Frant went on, “to look at his passbooks. I thought that if he had been investigating Eales’s past, he would probably have employed someone to do the donkey-work for him.”

“An enquiry agency, you mean?”

“Just so. There aren’t so many of them in London, and I carry most of their names in my head. I began with the passbooks of three years ago and it wasn’t very long before I came across a series of payments to Elderson.”

“Elderson?”

“Yes, the name struck me at once. You remember the clever little man who was in U Division and had to resign from the force over the Barkinshaw affair? He set up in business as a private enquiry agent in Shaftesbury Avenue.”

“I remember him perfectly well,” said Mallett. “I think we’ve had some trouble with him since. Wasn’t there rather a serious complaint from one of his clients a year or two ago?”

Frant nodded. “The complaint was withdrawn later,” he said, “but it gave friend Elderson a bad fright at the time. I thought that fact might come in handy if I had to put pressure on him, and so it turned out.”

“You went to see him, then?”

“Straight away. He was very smooth-spoken and ingratiating—just as he always used to be—until I told him what I’d come about. Then he turned difficult at once. He said he was very sorry, but his business being a highly confidential one, he made a point of keeping no record of his clients’ business. He showed me his advertisements, in which he guaranteed absolutely that all records were destroyed as soon as a case was concluded. They looked most impressive, I must say.” Frant chuckled at the recollection.

“Well?”

“Well, I reminded him of the affair we’ve just been speaking of, and suggested to him that if he wanted to put himself in a better light with Scotland Yard, perhaps it would be as well if he thought the matter over again.”

“Most immoral,” grunted the inspector.