“Well, what else?”
“The thought of Mercedes.”
“What had the thought of your sister to do with it?” asked Nick.
“It was the thought of what she would think of the matter that brought home to me the possibility that I had committed the crime in my sleep.”
“How so?”
“Simply because I have more than once told Mercedes—in jest of course, only she did not always believe that I was in jest—that some day I would kill Orizaba.”
“Indeed. You have often made that threat to her, have you?”
“A hundred times; perhaps more. Very often. I have even showed her the needle.”
“Ah! The needle again. You say you have shown it to your sister?”
“Yes; twice.”