"Why, sir?"
"On the evidence. You should always listen to evidence. Half the time it's a pack of lies, but you never know. In this case, all the witnesses say that Nathaniel was in a raging temper; and Brother Joseph admits that he was trying to smooth the old boy down, and getting ticked off for his pains. Followed him half-way up the stairs, he did. Now, if you were Nathaniel in a temper, being followed about by Joseph, what would you do?"
"I don't rightly know," said the Sergeant, staring.
"Then all I can say is you've taken more of a fancy to Joseph than I have. If I had a wind-bag like that on my tail, I'd lock my door, and very likely shove a heavy piece of furniture against it as well."
The Sergeant smiled, but ventured to say: "That's guess-work, sir."
"It is, which is why we won't treat it as more than a possibility," responded Hemingway, moving over to the door. "If I'm right, and Nathaniel locked this door himself, we haven't got to consider whether the murderer used a pencil and a bit of string to lock the door behind him, because he couldn't have unlocked it that way. What's more, they did have the sense to examine the door for signs of rubbing."
"Wouldn't hardly notice on these oak doors, would it?" suggested the Sergeant. "Not like soft paintwork which the string would cut into."
"No; but you'd be bound to see some trace under a magnifying-glass. Which would lead one to suppose that the murderer found the door locked, and turned the key from the outside."
"With an oustiti," nodded the Sergeant. "That's what I was thinking. Only there aren't any scratches on the key. If it weren't for that, I'd say an oustiti must have been used."
"That, and about half a dozen other reasons," interrupted his superior scathingly. "You aren't dealing with a professional burglary, my lad: this is an amateur job; and whoever heard of an amateur having a tool out of a professional's kit?"