When he reached a door near the end, he opened it and stood aside for them to enter.
"This is the room," he said, in a low voice.

It was Colwyn's keen eye that noted the key in the door.

"What is that key doing in the door, on the outside ?" he asked.

"How long has it been there ?" "The maid found it there this morning, sir, when she went up with Mr.
Glenthorpe's hot water.

That made her suspect something must be wrong, because Mr.Glenthorpe was in the habit of locking his door of a night and placing the key under his pillow.