"Then how did you learn? You certainly must have discovered something?"

The detective suddenly started and bent forward in a listening attitude.

"What is the matter, sir?" demanded Mr. Townsend.

"You have not kept faith with me, I fear," said Jack, in a tone of well-assumed sternness.

"I have not?"

"So it would appear."

"What do you mean?"

"There is some one in the adjoining room."

"Not to my knowledge."

"I heard a footstep."