The bell above the shop

An original fiction passage set in the nineteenth century.

Thomas had been told to lock the instrument-maker's shop before the owner returned from his journey. The rooms were empty, yet the bell above the front door gave a single chime. He waited for footsteps in the passage. None came.

On the counter, a trail of brass filings led towards the back room. Thomas brushed one into his palm. It was warm. The door there stood ajar, although he remembered closing it. Beyond it, the workshop was dark except for a narrow strip of lamplight beneath the storeroom door.

He crossed the floor without calling out. Something moved on the other side of the door: not a step, but a soft dragging sound, followed by a pause. Thomas put his hand on the latch. The bell above the shop rang again. When he turned, the front door was still locked, and a line of wet footprints, not his own, had appeared between it and the storeroom.

Analyse how the writer uses language and structure to build tension as Thomas searches the shop. Support your answer with references to the passage.