“No, I should think not, if they took this house for the express purpose of committing a crime in it.”

“Exactly.  And then there is one other fact that you may have gathered from our young friend’s remarks.”

“What is that?”

“That a controllable squint is a very valuable asset to a person who wishes to avoid identification.”

“Yes, I did note that.  The fellow seemed to think that it was absolutely conclusive.”

“And so would most people; especially in the case of a squint of that kind.  We can all squint towards our noses, but no normal person can turn his eyes away from one another.  My impression is that the presence or absence, as the case might be, of a divergent squint would be accepted as absolute disproof of identity.  But here we are.”

He inserted the key into the wicket of the large gate, and, when we had stepped through into the covered way, he locked it from the inside.

“Why have you locked us in?” I asked, seeing that the wicket had a latch.

“Because,” he replied, “if we now hear any one on the premises we shall know who it is.  Only one person besides ourselves has a key.”

His reply startled me somewhat.  I stopped and looked at him.

“That is a quaint situation, Thorndyke.  I hadn’t thought of it.  Why she may actually come to the house while we are here; in fact, she may be in the house at this moment.”

“I hope not,” said he.  “We don’t particularly want Mr. Weiss to be put on his guard, for I take it, he is a pretty wide-awake gentleman under any circumstances.  If she does come, we had better keep out of sight.  I think we will look over the house first.  That is of the most interest to us.  If the lady does happen to come while we are here, she may stay to show us over the place and keep an eye on us.  So we will leave the stables to the last.”

We walked down the entry to the side door at which I had been admitted by Mrs. Schallibaum on the occasion of my previous visits.  Thorndyke inserted the latch-key, and, as soon as we were inside, shut the door and walked quickly through into the hall, whither I followed him.  He made straight for the front door, where, having slipped up the catch of the lock, he began very attentively to examine the letter-box.  It was a somewhat massive wooden box, fitted with a lock of good quality and furnished with a wire grille through which one could inspect the interior.

“We are in luck, Jervis,” Thorndyke remarked.  “Our visit has been most happily timed.  There is a letter in the box.”

“Well,” I said, “we can’t get it out; and if we could, it would be hardly justifiable.”

“I don’t know,” he replied, “that I am prepared to assent off-hand to either of those propositions; but I would rather not tamper with another person’s letter, even if that person should happen to be a murderer.  Perhaps we can get the information we want from the outside of the envelope.”