“Surely, you don’t think I—”
“Could you?”
“Yes, but—”
“Well, now, look,” I said, importing a sudden harshness into my tones, “you hated the thought of marrying Sir Philip and his death would mean your release, besides which it would mean wealth to your brother and a happy issue from his financial—”
“But the suggestion is infamous, intolerable!” Thoyne cried.
“Don’t be a fool,” I advised him. “I am not accusing Miss Clevedon; I am summarising the case against her brother. The first essential is to establish a motive and there you have one twice over—Sir Philip’s death would release his sister from a hateful marriage and it would—he would succeed to the dead man’s title and money. I am being purposely brutal because I want to put it at its worst. He comes to Midlington, a few miles from Cartordale on the day before the tragedy, he leaves Midlington for some unknown destination, which may, however, have been Cartordale, a few hours before the murder, he knows a secret way into White Towers, and he has a dual motive for assassinating Sir Philip. You have summed all this up in your own minds, haven’t you? It has been a dark shadow in your thoughts ever since that tragic day. Isn’t that so?”
There was a long silence.
“Yes,” Thoyne said at length, “you are perfectly right. You have described exactly what, as I said before, has been a ceaseless nightmare to us. And you have omitted the main difficulty. Why doesn’t he come to Cartordale?”
“But, now,” I went on, “let us take the other side. There is no evidence of any sort that Clevedon ever had any prussic acid in his possession. Or is there?”
“We know of none,” Thoyne assented eagerly.