"That? Oh, that, I believe, opens on to a passage which leads to the caretaker's quarters. Very estimable people, the Perrys, mother and daughter, and I should say the Institute people will be sorry to lose them. They are moving, as you noticed, and into the country. This door, though, has been kept locked and screwed up--you can see the screws for yourself, can't you?--so there has been no possible means of ingress or egress. Anything else, Mr. Headland?" Mr. Headland shook his head dolefully. "Nothing to be learned here. I think I'd like to get that address, the old woman's, you know," he added, meekly. "Oh, that! Still thinking of that elderly Venus, eh? Well, I'll go and find Thompson for you myself," said the now openly sneering Mr. Belthouse. "Any ideas, old chap?" whispered Mr. Narkom, as his ally bent down and touched another few flakes of plaster-like white powder. "Bushels," was the laconic reply. "But when a mouse gets into a trap, what does it do?" "Why, stays in, of course!" said the mystified Narkom, and Cleek gave a little satisfied laugh as he lurched to the end of the hall where Mr. Charles Galveston Belthouse, in a supremely bad temper, arrived a moment later in company with the stalwart commissionaire, Thompson. "No go, sir; no sign of that blessed cab, and the taxi men never noticed it on the stand before. They are rare in these parts nowadays, sir. I hardly expected to get one, only the good lady was set on it. Said she wouldn't go near one of those dangerous motor things, and the way she sniffed even at the cabby----!" A queer little smile crept round Mr. Headland's mouth. "It's of no importance, my man. I don't think we shall want either the cab or the good lady again." The man returned to his own post, and Cleek followed the secretary from the gallery. But a little distance away he stopped short, feeling in his pocket, then uttered a little cry of dismay. "I thought I heard it. Excuse me, sir, it's my pen. I dropped it. Won't keep you waiting a minute." He turned and ran swiftly back, returning some three minutes later, the pen in his hand, a smile on his face, and still further patches of white on his coat that would have suggested to even a less keen observer than Mr. Narkom that he had been very near to the ceiling. "And now to see the body, Mr. Belthouse," he said, briskly, looking placidly at that gentleman's perturbed face as he opened the door of a little room wherein had been borne the body of the unfortunate policeman. CHAPTER XXVII THE RUSE OF THE SPRAINED WRIST The body was that of a man in the very prime of life, and but for the strangely set and rigid face might have been thought that of one asleep. Cleek examined it minutely, even pulling down the lips and raising the closed eyelids. For a moment he stood looking down at the still figure, then he shut up his magnifying glass with a snap.