s still in the dining-room
on their return. The papers Durham had placed on the table were
untouched.

"I am sorry to have had to detain you, Mrs. Eustace. For the present I
have nothing further to ask you. These papers you had better take--I
have no doubt they were left for you."

"What do you mean--left for me?" she exclaimed.

"A woman of your quick intelligence, Mrs. Eustace, scarcely needs to be
told," he answered, adding, as he turned to Harding, "I would like a few
moments with you in the office."

In the little ante-room that Eustace had used as his private office,
Durham turned the searchlight of his questions upon Harding.

"Have you known Mr. Eustace for very long?"

"I have only known him personally since I came to this branch a few
weeks ago."

"Did you apply to be sent here?"

"No. I knew nothing about it until I received instructions to come."

"Did you know Mrs. Eustace before you came here?"

"Not as Mrs. Eustace."

"You knew her before she was married?"

"Yes."

"Well?"

"Yes."

"Am I right in saying that you knew her very well?"

"Yes, I did know her very well."

"Don't think I am attempting to pry into your private affairs, Mr.
Harding. In a case of this kind, the clues that lead to the unravelling
of the mystery often lie on the surface in some trifling circumstance
that seemingly has nothing whatever to do with the main question. You
have already realised, I take it, that we are concerned with something
quite distinct from the ordinary class of crime. Perhaps you have not
had sufficient experience with the criminal class to recognise what was
apparent to me from the beginning, that in this matter we are following
the work of one who is a master of his craft."

"So far as that goes, I am absolutely dazed," Harding exclaimed. "The
more I hear, the more hopelessly confused I grow."

"I am not surprised. You are following the work of someone who is, I am
quite satisfied, no ordinary criminal, but one of the most astute,
clever and unscrupulous individuals who ever adopted dishonesty as a
profession. If I ask you questions which appear to you to be irrelevant
and possibly impertinent, will you give me credit for being actuated
only by my sense of duty, and answer those questions as fully and as
accurately as you can?"

"Certainly," Harding replied.

"Thank you. Now, will you tell me this--Were you ever engaged to Mrs.
Eustace before she married her present husband?"

"Yes.