"Of course any one trying to copy another man's hand would make his letters the same," she retorted, "but the character isn't the same. Can't you see?"

"There is a slight difference," I admitted, "but I really can't honestly say I see any sufficient ground for putting this down as a fake. Besides, what do you suppose it is—a practical joke?"

"No, of course not. It was written by the real murderer to put people off the scent."

I tried not to smile, but I am afraid I did.

"Another brilliant guess!" I said, and then hastened to add, "But a most ingenious one and quite possibly—very probably, in fact, you are right."

But she saw through my compliments, and I felt rather than observed an instant change in her.

"Oh, you may be right," she said, and handed me back the pocket book.

"Or wrong," I replied, "but I mean to try and discover which."

Instead of asking me what I meant to do, as I feared and expected, she walked by my side very thoughtfully and in silence. I gave her a moment or two to put the question which never came, and then changed the subject.

"And have you discovered anything?" I asked.