The Big Time by Fritz Leiber

"We examined the moss between the bricks, and found it undisturbed. " "You looked among D -- -- 's papers, of course, and into the books of the library? " "Certainly; we opened every package and parcel; we not only opened every book, but we turned over every leaf in each volume. " -- Poe

Three hours later, Sid and I plumped down on the couch nearest the kitchen, though too tired to want to eat for a while yet. A tighter search than I could ever have cooked up had shown that the Maintainer was not in the Place.