He was peering over Walter Hine's shoulder.
Again Chayne whistled and, not content with whistling, he cried out in a feigned bucolic accent: "I see you." At once Garratt Skinner's head disappeared altogether.
Walter Hine peered down into the darkness whence the whistle came, curving his hands above his forehead to shut out the light behind him; and behind him once more the shadow appeared upon the ceiling and the wall.

A third time Chayne whistled; and Walter Hine cried out: "What is it ?" And behind him the shadow vanished from the ceiling and the door began to close, softly and stealthily, just as softly and stealthily as it had been opened.
Again, Hine cried out: "Who's there?
What is it ?" And Chayne laughed aloud derisively, as though he were some yokel practising a joke.

Hine turned back into the room.

The room was empty, but the door was unlatched.

He disappeared from the window, and the watchers below saw the door slammed to, heard the sound of the slamming and then another sound, the sound of a key turning in the lock.
It seemed almost that Chayne had been listening for that sound.