“I have formed no conclusion whatever,” my companion answered.
“But we formed ours yesterday, and now it proves to be correct, so you must acknowledge that we have been a little in front of you this time, Mr. Holmes.”
“You certainly have the air of something unusual having occurred,” said Holmes.
Lestrade laughed loudly.
“You don’t like being beaten any more than the rest of us do,” said he. “A man can’t expect always to have it his own way, can he, Dr. Watson? Step this way, if you please, gentlemen, and I think I can convince you once for all that it was John McFarlane who did this crime.”
He led us through the passage and out into a dark hall beyond.
“This is where young McFarlane must have come out to get his hat after the crime was done,” said he. “Now look at this.” With dramatic suddenness he struck a match, and by its light exposed a stain of blood upon the whitewashed wall. As he held the match nearer, I saw that it was more than a stain. It was the well-marked print of a thumb.
“Look at that with your magnifying glass, Mr. Holmes.”
“Yes, I am doing so.”
“You are aware that no two thumb-marks are alike?”
“I have heard something of the kind.”
“Well, then, will you please compare that print with this wax impression of young McFarlane’s right thumb, taken by my orders this morning?”
As he held the waxen print close to the blood-stain, it did not take a magnifying glass to see that the two were undoubtedly from the same thumb. It was evident to me that our unfortunate client was lost.