All need for caution was gone now. Foyle had dropped his jemmy and his hand closed over his pistol. Only as a last resource would he use it, but if he had to--well, there could be no harm in having it handy. A door slammed as the two detectives climbed the second flight of stairs. Green flung himself against the one that had been indicated by Israels, and the flimsy fastening gave way under the shock of his thirteen stone. There was no one in the room. Savagely Heldon Foyle turned and caught the handle of a second door. It turned, and they entered the room, empty like the first, but with an open window looking out on a series of low roofs a dozen feet below. And over the roofs a shadowy figure of a man was clambering hurriedly. He could only dimly be seen. Green clambered through on to the window-sill and dropped. He was unlucky. A projecting piece of wood caught his foot, and he staggered and lost time. Before he had recovered himself the fugitive was out of sight, and the sound of his progress had ceased. Foyle called to him to come back and, without waiting to see whether his orders were obeyed, made his way back again to the first-floor landing. Israels was still there, very white and shaky, as the superintendent struck a match. "Where's that girl?" said the detective curtly. "The one who gave the alarm." "My daughter? She thought you were burglars. She didn't know." "Where is she?" Without waiting for a reply he entered the room whence she had emerged and, striking another match, applied it to a gas-bracket. A fat woman was sitting up in bed looking at him timorously. He paid no heed to her, but stooped to look under the bed. When he straightened himself Green had rejoined him. "The girl gave us away," exclaimed Foyle. "Here, you, where is she gone?" He shook the woman roughly by the shoulder. "Go to the bottom of the stairs, Green, and see that no one slips in or out. Take that chap outside down with you." "My daughter?" exclaimed the woman helplessly. "She has gone to stay with her aunt. We are respectable people. You frightened her. We don't like the police coming here." "Highly respectable," repeated Foyle under his breath. Aloud he said menacingly, "We shall soon know whether you are respectable. Where does the girl's aunt live?" "Twenty-two Shadwell Lane," was the reply, glib and prompt. Foyle looked for an instant penetratingly at her. Her eyes dropped. His hand went to his pocket and he calmly lighted a cigar. Then he went downstairs to where Green was on guard and politely apologised to Israels. Casually he repeated the question he had put to the woman. Yes, the Jew had seen his daughter go out. She said she was going to her aunt. Her aunt lived at 48 Sussex Street.