“You have taken a load off my mind,” I returned cheerfully. “But are you quite sure? Sudden temptation, you know, and—and so on.”
“Ah, you are pulling my leg, Mr. Holt,” Pepster replied affably.
“But you did suspect me,” I urged, wondering how far the detective might be amenable to pumping.
Some of them are, but not those who know their job.
“Well, suspect—that’s rather a big word,” Pepster said thoughtfully. “You see, the law says a man is innocent until he is proved guilty, but a detective who knows his business proceeds the other way about. Everybody is guilty in his eyes until the facts prove their innocence. There is only one man I am absolutely sure did not commit this murder, and that is myself, but nobody save me has any call to be sure even of that. Now you, for example—could you prove an alibi for that night if I took it into my head to charge you?”
“We will suppose I could not—for the sake of argument.”
“Just so, but then, you see, something else is required. Society is based on a notion that ordinary, normal men act in an ordinary, normal manner and don’t go about murdering each other for the mere fun of the thing. It is like people walking along a city pavement while motor-cars are dashing to and fro in the roadway. The three or four inches by which the pavement is raised are no protection at all should a motor-car take a sudden swerve, but pedestrians go ambling quietly on in the knowledge that the normal thing is for motor-cars to keep their own place, and that when they go wrong it is because something has happened. Yes, Society is based on the prevalence of the normal. When you hear, for instance, that one man has killed another, you take it for granted there was a reason—what we call a motive. And the motive is vital. Sometimes the why of a murder reveals the who, and sometimes the who explains the why. But the two must go together.”
“Your philosophy is both interesting and accurate,” I said. “And what of the hatpin?”
“Ah, the hatpin,” Pepster replied thoughtfully. “But that may have been an accident and not the woman in the case.”
“The woman?” I said inquiringly, my thought going instantly to my midnight visitor. “Yes, of course, a hatpin does suggest a woman, doesn’t it?”