She had been in the room, then.  For what object?  For the reasons stated in her confession?  Crewe shook his head doubtfully.

“She evaded the trap about the pocket-book, but she made one bad mistake,” he mused.  “The letters in the secret drawer were taken away, and I have no doubt were burnt as she says.  But were they her letters?  Was Sir Horace her lover?  At any rate, she did not get hold of them in the way she said.  They were not taken away on the night Sir Horace was murdered, for the simple reason that they were not in the secret drawer at the time.”

CHAPTER XXIV

Rolfe was spending a quiet evening in his room after a trying day’s inquiries into a confidence trick case; inquiries so fruitless that they had brought down on his head an official reproof from Inspector Chippenfield.

Rolfe had left Scotland Yard that evening in a somewhat despondent frame of mind in consequence, but a brisk walk home and a good supper had done him so much good, that with a tranquil mind and his pipe in his mouth, he was able to devote himself to the hobby of his leisure hours with keen enjoyment.

This hobby would have excited the wondering contempt of Joe Leaver, whose frequent attendance at cinema theatres had led him to the conclusion that police detectives—­who, unlike his master, had to take the rough with the smooth—­spent their spare time practising revolver shooting, and throwing daggers at an ace of hearts on the wall.  Rolfe’s hobby was nothing more exciting than stamp collecting.  He was deeply versed in the lore of stamps, and his private ambition was to become the possessor of a “blue Mauritius.”  His collection, though extensive, was by no means of fabulous value, being made up chiefly of modest purchases from the stamp collecting shops, and finds in the waste-paper-baskets at Scotland Yard after the arrival of the foreign mails.

That day he had made a particularly good haul from the waste-paper-baskets, for his “catch” included several comparatively good specimens from Japan and Fiji.  He sat gloating over these treasures, examining them carefully and holding each one up to the light as he separated it from the piece of paper to which it had been affixed.  He pasted them one by one in his stamp album with loving, lingering fingers, adjusting each stamp in its little square in the book with meticulous care.  He was so absorbed in this occupation that he did not hear the ascending footsteps drawing nearer to his door, and did not see a visitor at the door when the footsteps ceased.  It was Crewe’s voice that recalled him back from the stamp collector’s imaginary world.

“Why, Mr. Crewe,” said Rolfe, with evident pleasure, “who’d have thought of seeing you?”

“Your landlady asked me if I’d come up myself,” said Crewe, in explaining his intrusion.  “She’s ’too much worried and put about, to say nothing of having a bad back,’ to show me upstairs.”