“Let us say letter-delaying. I got on to this business owing to the fact that all the letters that came to me from my stationer and from a friend of mine in a Government office were unaccountably delayed twenty-four hours in the post. After giving the matter some thought I reached the conclusion that this coincidence was due to the fact that they were both enclosed in blue envelopes.” “How is Braime?” asked the sergeant. “Better,” was the reply. “I had a talk with him to-night--he’s had the shock of his life.” He chuckled softly, though his heart at that precise moment was aching for the dazed and indignant girl who was occupying the matron’s room, a large and airy cell, at the Chelsea police station. The cab stopped before Hiles Mansions, and the lift-man took them up to Michael’s cosy flat. There were two or three letters waiting for him in his letter-box. He took them out and examined them. Then he went on to the landing and rang for the elevator. “You brought these letters up?” “Yes, sir.” “What time did they arrive?” “Half-past nine, sir,” said the man. “There was a blue envelope posted to me this afternoon at three-thirty. It’s not here. How do you account for that?” The liftman looked past him. “I’m sure I can’t tell you, sir,” he said, studiously avoiding Michael’s eyes. “I bring the letters up as they come and put ’em in your box.” “You’re on duty from nine at night until nine in the morning, aren’t you?” asked Dorn. “Yes, sir.” “You handle the morning and the night posts. Why is it that all letters enclosed in blue envelopes fail to reach me until twenty-four hours after they are due?” “I can’t tell you that, sir.” “Tell this gentleman. He’s a detective from Scotland Yard. And tell him without hokum, or you’ll sleep uncomfortably to-night, my friend.” For a while the man blustered and protested and then suddenly collapsed. “I’ve got a wife and four children,” he whined, “and there’s an Army pension I shall lose----” “You’ll lose nothing if you tell me the truth. Who employed you to stop my letters?” “A man, sir. I don’t know his name. If I die this minute, I don’t know his name! He gives me two pounds a week to hold up all the blue envelopes and the official ones. They’re not stolen, sir, they’re always put into the letter-box----” “I know all about that,” interrupted Michael curtly. “You’re wasting your breath, man. Who is your employer?” “I swear I don’t know him, sir. I met him at a public-house one night. He kidded me on to this job. I wish I’d never seen him.” “Does he call for the letters?” “Yes, sir, he called this morning after the post came in, but I didn’t give him the blue envelope because I hadn’t got it then. The postman overlooked it and came back a quarter of an hour later.” “The blue envelope? Which blue envelope?” asked Michael quickly. “It is downstairs, sir,” whimpered the unfaithful servant of Hiles Mansions. “We’ll go down with you and get it.”