I left the sentence unfinished, and helped myself to a second bit of bread and butter.

There was a short silence.

“Tell me about George, Joyce,” I went on.  “What are these particular dark doings that Tommy’s hinting about?”

Joyce leaned forward with her chin on her hands, her blue eyes fixed on mine.

“Neil,” she said slowly, “I’ve found out something at last—­something I thought I was never going to.  I know who the man was in Marks’s rooms on the day that he was murdered.”

I was so surprised that I gulped down a mouthful of nearly boiling tea.

“I wish you’d break these things more gently, Joyce,” I said.  “Who was it?”

“It was Dr. McMurtrie.”

I put down the teacup and stared at her in the blankest amazement.

“Dr. McMurtrie!” I repeated incredulously.

She nodded.  “Listen, and I’ll tell you exactly how it all happened.  I dined with George, as you know, at the Savoy on Friday, and we went into the whole business of my going away with him.  He has got that twelve thousand pounds, Neil; there’s no doubt about it.  He showed me the entry in his pass-book and the acknowledgment from the bank, and he even offered to write me a cheque for a couple of hundred right away, to buy clothes with for the trip.”

“From what I remember of George,” I said, “he must be desperately in love with you.”

Joyce gave a little shiver of disgust.  “Of course I let him think I was giving way.  I wanted to find out where the money had come from, but try as I would, I couldn’t get him to tell me.  That makes me feel so certain there’s something wrong about it.  In the end I arranged to dine with him again tomorrow night, when I said I’d give him my final answer.  On Saturday morning, however, I changed my mind, and wrote him a note to say I’d come Thursday instead.  I didn’t mean to tie myself to be back tomorrow, in case you wanted me here.”

She paused.

“I had to go up Victoria Street, so I thought I’d leave the letter at his office.  I’d just got there, and I was standing outside the door opening my bag, when a man came down the steps.  I looked up as he passed, and—­oh Neil!—­it was all I could do to stop myself from screaming.  I knew him at once; I knew his cold wicked face just as well as if it had been only three days instead of three years.  It was the man I’d seen in Marks’s rooms on the afternoon of the murder.”

She stopped again, and took a deep breath.

“I was horribly excited, and yet at the same time I felt quite cool.  I let him get about ten yards away down the street, and then I started off after him.  He walked as far as the Stores.  Then he called an empty taxi that was coming past, and I heard him tell the driver to go to the Hotel Russell.  I thought about how you’d followed the man with the scar, and I made up my mind I’d do the same thing.  I had to wait for several seconds before another taxi came by, but directly it did I jumped in and told the man to drive me to the corner of Russell Square.