He might have been looking.

At any rate it reminded her unpleasantly of the fact that there were detectives in the world.
"What's the matter ?" asked Graeme, noticing the change in her.
"I just saw a man I know." The old jealousy flushed his face.

Constance laughed in spite of her fears.

Indeed, there was something that pleased her in his jealousy.
"He was the detective who has been hounding me ever since that time I told you about." "Oh," he subsided.

But if Drummond had been there, Mackenzie could have been counted on to risk all to protect her.
"We must be more careful," she shuddered.
Constance was startled one evening just as she was going out to meet Graeme and report on the progress of the day at hearing a knock at her door.
She opened it.
"I suppose you think I am your Nemesis," introduced Drummond, as he stepped in, veiling the keenness of his search by an attempt to be familiar.
She had more than half expected it.