“Yes, but you didn’t start.”

“It was a piece of stupid luck that saved me when I ought to have known, when I ought to have been sure.  And, mark you, if I had come back believing in Groener’s innocence, this crime would never have been cleared up, never.”

Tignol shrugged his shoulders.  “La, la, la!  What a man!  If you had fallen into a hole you might have broken your leg!  Well, you didn’t fall into the hole!”

Coquenil smiled.  “You’re right, I ought to be pleased, I am pleased.  After all, it was a neat bit of work.  You see, I was waiting in the parlor of this boarding house for the widow to bring me my bill—­I had spent two days there—­and I happened to glance at a photograph she had shown me when I first came, a picture of Alice and herself, taken five years ago, when Alice was twelve years old.  There was no doubt about the girl, and it was a good likeness of the widow.  She told me she was a great friend of Alice’s mother, and the picture was taken when the mother died, just before Alice went to Paris.

“Well, as I looked at the picture now, I noticed that it had no photographer’s name on it, which is unusual, and it seemed to me there was something queer about the girl’s hand; I went to the window and was studying the picture with my magnifying glass when I heard the woman’s step outside, so I slipped it into my pocket.  Then I paid my bill and came away.”

“You needed that picture,” approved Tignol.

“As soon as I was outside I jumped into a cab and drove to the principal photographers in Brussels.  There were three of them, and at each place I showed this picture and asked how much it would cost to copy it, and as I asked the question I watched the man’s face.  The first two were perfectly businesslike, but the third man gave a little start and looked at me in an odd way.  I made up my mind he had seen the picture before, but I didn’t get anything out of him—­then.  In fact, I didn’t try very hard, for I had my plan.

“From here I drove straight to police headquarters and had a talk with the chief.  He knew me by reputation, and a note that I brought from Pougeot helped, and—­well, an hour later that photographer was ready to tell me the innermost secrets of his soul.”

“Eh, eh, eh!” laughed Tignol.  “And what did he tell you?”

“He told me he made this picture of Alice and the widow only six weeks ago.”

“Six weeks ago!” stared the other.  “But the widow told you it was taken five years ago.”

“Exactly!”

“Besides, Alice wasn’t in Brussels six weeks ago, was she?”

“Of course not; the picture was a fake, made from a genuine one of Alice and a lady, perhaps her mother.  This photographer had blotted out the lady and printed in the widow without changing the pose.  It’s a simple trick in photography.”

“You saw the genuine picture?”

“Of course—­that is, I saw a reproduction of it which the photographer made on his own account.  He suspected some crooked work, and he didn’t like the man who gave him the order.”