“Which is his room?” said French, grimly. This should be a lesson to him to avoid his confounded trick of waiting till he was sure. If this man had slipped through his hands, any chance of that chief inspectorship was gone—if his job itself remained. They went to a first-floor room at the back of the house and French knocked peremptorily. There was no reply. “Down with the door, Carter. Put your shoulder to it with me.” Despite the protests of the landlady, both men threw themselves on the door. With a tearing sound the screws of the keeper drew out and the door swung open. The room was empty. It was a large room, comfortable furnished as a bed-sitting room. It was not disarranged in any way, but the lower sash of the window was fully up. French hurriedly crossed to it and looked out. It gave on the yard, and about four feet below the sill was the roof of a small shed. This shed ran along the side of the yard at right angles to the main house, its further gable being against the wall between the yard and the lane which passed at the back of the houses. The roof of the shed formed a direct passage from the room to the lane. Though French had no doubt that Pyke had escaped by this route, he dropped out of the window and crawled over the roof tiles, searching for traces. These he speedily discovered. Some one had passed a short time previously. His chagrin was too deep for words. Even the lurid phrase with which in times of stress he was wont to relieve his feelings now proved utterly inadequate. He was aghast at the extent to which he had been hoodwinked. For it was now evident that Pyke had known he had been shadowed to Hampstead Heath and that the whole conversation there had been designed to put him, French, off the track. Pyke was a cleverer man than he had thought. It seemed scarcely possible that the interview had been prearranged, and yet French could not imagine its being an improvisation. The whole thing was very puzzling. However, at least one thing was clear. Jefferson Pyke and Mrs. Berlyn were the criminals for whom he was seeking. And he was on a hot scent. He would get Mrs. Berlyn at once, and Pyke with very little delay. The man had less than twelve hours’ start. He turned to Carter. “Wait here for me, Carter,” he directed. “Have a look round and learn anything you can, but without disturbing things. I shall be back presently.” He ran out of the house, and calling up his taxi, was driven to Park Walk. There he soon spotted the man who was shadowing Mrs. Berlyn. “Anything to report, Jefferies?” he demanded, quickly. “She’s still there, all right?” “Still there, Mr. French. No one left the house since I came on duty.” “Good. Then come with me.” He rang at the door and, when the servant opened, asked for Mrs. Berlyn.