The Sign of the Stranger by William le Queux

Along the dark street, quiet after the glare and bustle of the King's Road, I retraced my steps, when, about half-way up, I met a man dressed as a mechanic, idly smoking a pipe. He glanced quickly at me as I passed beneath the light of a street-lamp, and I guessed from his searching look that he was the detective Bullen.

Without apparently taking notice of him I went along almost to the end of the street, until I discovered that the house which Lolita had indicated differed little from its neighbours save that it was rendered a trifle more dingy perhaps by the London smoke. And yet the large printed numerals on the fanlight over the door gave it a bold appearance that the others did not seem to possess. The area was a deep one, but the shutters of the kitchen window were tightly closed. With the exception of the light in the hall the place seemed in darkness, presenting to me a strange, mysterious appearance, knowing all that I did. Why, I wondered, was that police officer lounging up and down keeping such a vigilant surveillance upon the place? Surely it was with some distinct motive that a plain-clothes man watched the house day and night, and to me that motive seemed that they expected that some person, now absent, might return.