Hewitt saw her to his office door, and waited till she had half descended the stairs. Then he made for a staircase window which gave a view of the street. The evening was coming on murky and foggy, and the street lights were blotchy and vague. Outside a four-wheeled cab stood, and the driver eagerly watched the front door. When Mrs. Mallett emerged he instantly began to descend from the box with the quick invitation, “Cab, mum, cab?” He seemed very eager for his fare, and though Mrs. Mallett hesitated a second she eventually entered the cab. He drove off, and Hewitt tried in vain to catch a glimpse of the number of the cab behind. It was always a habit of his to note all such identifying marks throughout a case, whether they seemed important at the time or not, and he has often had occasion to be pleased with the outcome. Now, however, the light was too bad. No sooner had the cab started than a man emerged from a narrow passage opposite, and followed. He was a large, rather awkward, heavy-faced man of middle age, and had the appearance of a respectable artisan or small tradesman in his best clothes. Hewitt hurried downstairs and followed the direction the cab and the man had taken, toward the Strand. But the cab by this time was swallowed up in the Strand traffic, and the heavy-faced man had also disappeared. Hewitt returned to his office a little disappointed, for the man seemed rather closely to answer Mrs. Mallett’s description of Reuben Penner. [Illustration: “‘CAB, MUM?’”] II Punctually at half-past ten the next morning Hewitt was at Mrs. Mallett’s house at Fulham. It was a pretty little house, standing back from the road in a generous patch of garden, and had evidently stood there when Fulham was an outlying village. Hewitt entered the gate, and made his way to the front door, where two young females, evidently servants, stood. They were in a very disturbed state, and when he asked for Mrs. Mallett assured him that nobody knew where she was, and that she had not been seen since the previous afternoon. “But,” said Hewitt, “she was to stay at her sister’s last night, I believe.” “Yes, sir,” answered the more distressed of the two girls--she in a cap--“but she hasn’t been seen there. This is her sister’s servant, and she’s been sent over to know where she is, and why she hasn’t been there.” This the other girl--in bonnet and shawl--corroborated. Nothing had been seen of Mrs. Mallett at her sister’s since she had received the message the day before to the effect that the house had been broken into. “And I’m so frightened,” the other girl said, whimperingly. “They’ve been in the place again last night.” “Who have?” “The robbers. When I came in this morning----” “But didn’t you sleep here?” “I--I ought to ha’ done, sir, but--but after Mrs. Mallett went yesterday I got so frightened I went home at ten.” And the girl showed signs of tears, which she had apparently been already indulging in.