"I believe I can," she said, after a moment's thought. "She wrote a store's order the other day which was not sent. I believe it's in this drawer. Yes, here it is."

I glanced at it and put it in my pocket.

"I wonder whether this nephew has anything to do with the affair?" I said contemplatively.

"No," she said with decision.

"Why are you so certain? You said you didn't know him."

"I don't."

"I have discovered one thing," I said carelessly. "By Mrs. Jardine's death he comes into a lot of money."

"I've heard my mistress say something of the kind."

"You see, there would be a motive for the murder."

"The thing is to find Mrs. Harrison," she said. "A woman doesn't go away in the middle of the night unless she has a good reason for doing so."