The inspector failed to follow this reasoning. “Why do you say that?” he asked. “I can’t see it at all.”
“Well, it is clear that the murderer, whoever he was, did his level best to get Walter Brooklyn hanged. Who stood to gain by getting Walter Brooklyn out of the way?”
“I see. Carter Woodman. Yes, I follow now.”
“That is one strong point against him. Here is another. Do you remember where Walter Brooklyn thought he had left his stick on Tuesday afternoon? He went back to look for it, you remember.”
The inspector thought for a moment. “In Carter Woodman’s office,” he said at last.
“Well, then, isn’t it clear that he did leave his stick in Woodman’s office? Woodman found it, but denied the fact when Walter called to fetch it, and told him he must have left it in the taxi. Then Woodman deliberately planted the stick on the scene of Prinsep’s murder.”
“That’s pure hypothesis. I don’t say it isn’t true; but——”
“It’s more than hypothesis: it is divination. Surely you see that it must be what happened.”
“I expect, as usual, you are right,” said the inspector. “But will it convince a jury? I have tried all I know to get any evidence showing when the stick was left; but not a trace can I find. A jury will regard it as a pure hypothesis.”
The superintendent sighed. Juries are sadly lacking in appreciation of the subtleties of reasoning. “You’re quite right there,” he said. “My divination won’t hang Carter Woodman. But it convinces you as it convinced me. We have to get faith in our own knowledge before we can make a case that will persuade others. You and I now have that faith. We know that Carter Woodman is guilty.”