The Mystery of the Phantom Grasshopper — Kathryn Kenny

The heavy front door closed solidly behind Trixie. . . . The long corridor that ran past the stairway was dark and gloomy-looking, and the stillness of the old building made Trixie feel she should walk softly. . . . She had almost reached the stairs when she saw a door directly across from the stairway open slowly. A tall man backed out into the hall and soundlessly closed the door. Turning, he saw Trixie....