The last time the thread must have slipped or possibly the point of the pin had caught in the wood-work of the door and had fallen where he had found it. Or the man may have left it in the vault and it had been left in the passage after Trasmere’s death to add mystery to mystery. “Did you see?” Lander’s voice shook with pride. “Simple, eh? And quick, Tab?” Tab did not answer. “I am a rotten architect, eh, Tab, but by Jingo, I’m a good bricklayer! Have you seen me lay bricks, Tab? I know so much about it that I fired the two workmen today, and said I was going to get somebody else to finish the job, Tab, I’m finishing it.” Tab crossed his hands and tried to snap the connecting links of the cuff, but he could not get purchase. He had been so tied that he could hardly move. His head was aching terribly and he knew the cause; one of the first things he had seen on recovering consciousness, was the sand-bag which Rex Lander had used as he was leaning across the table, fooled into believing that some secret passage would be revealed when he pulled. Rex was singing softly and mingled with his voice came the click and ring of trowel on brick, that scraping sound that bricklayers make, that tap, tap, tap of the trowel as it knocked the bricks into place. “I shall probably be working all night,” Lander interrupted his singing to say, talking with his mouth against the ventilator. “I ought to have put the light out, but it is too late now.” “You poor lout,” said Tab contemptuously. “You poor cheap lunatic! I can’t be angry with you, you unspeakable fat man!” He heard the quick intake of the other’s breath and knew that he had touched him on the raw. “Don’t you realise,” said Tab remorselessly, “that the very first place Carver will look will be this vault and when he finds it is bricked up, the very first thing he will do, will be to tear it down and all your fine explanations will not stop him. And then what will he find? The confession, which, in your crazy vanity, you have made, and my statement.” “You’ll be dead,” howled Lander and went to work frantically. XXXIII Tab’s brain was clearing now; he was taking a cold survey of the position. Rex Lander was mad--up to a point. Mad as men of abnormal vanity are mad. Vanity inspired the bravado which made him leave in the deathroom a statement which would surely hang him when it was found. Vanity and hurt pride led him to his present dreadful act, even as it had led him to search amongst Tab’s papers at the flat for Ursula’s non-existent love letters and to tear and mutilate the portrait of the man who had won her love. Rex was the burglar. Who else could have found his way unerringly in the dark? And Carver had known!