all, Mr. Munro?' asked Barton. 'Yes. I quite agree with you, sir, the more we probe this mystery, the more and more complicated it becomes.'

'Well, Mr. Barton?' I exclaimed. 'Now, tell me frankly, what's your theory. Why has Miss Lethmere disappeared?'

The inspector, one of the best and shrewdest officials attached to the Criminal Investigation Department, paused for a few moments and, looking me full in the face, replied:

'To tell you the truth, Mr. Munro, I'm still absolutely puzzled. The whole affair seems to grow more involved, and more astounding.'