Langhorne now but ill concealed his interest.  It was natural, too, for here he had one of the most modern of small strong-boxes, built up of the latest chrome steel and designed to withstand any reasonable assault of cracksman or fire.

I was on the point of inquiring how on earth it had been possible to rob the safe, when Kennedy, standing on a chair, as Langhorne directed, uttered a low exclamation.

I craned my neck to look also.

There, in the very top of the safe, yawned a huge hole large enough to thrust one’s arm through, with something to spare.

As I looked at the yawning dark hole in the top of what had been only a short time ago a safe worthy of the latest state of the art, it seemed incomprehensible.

Try as I could to reason it out, I could find no explanation.  How it had been possible for a burglar to make such an opening in the little more than two hours between closing and the arrival of Langhorne after dinner, I could not even guess.  As far as I knew it would have taken many long hours of patient labour with the finest bits to have made anything at all comparable to the destruction which we saw before us.

A score of questions were on my lips, but I said nothing, although I could not help noticing the strange look on Langhorne’s face.  It plainly showed that he would like to have known what had taken place during the two or more hours when his office had been unguarded, yet was averse to betraying any such interest.

Mystified as I was by what I saw, I was even more amazed at the cool manner in which Kennedy passed it all by.

He seemed merely to be giving the hole in the top of the safe a passing glance, as though it was of no importance that someone should have in such an incredibly short time made a hole through which one might easily reach his arm and secure anything he wanted out of the interior of the powerful little safe.

Langhorne, too, seemed surprised at Kennedy’s matter of fact passing by of what was almost beyond the range of possibility.

“After all,” remarked Kennedy, “it is not the safe that we care to study so much as the door.  For one thing, I want to make sure whether the marks show a genuine breaking and entering or whether they were placed there afterwards merely to cover the trail, supposing someone had used a key to get into the office.”

The remark suggested many things to me.  Was it that he meant to imply that, after all, the missing Betty Blackwell had had something to do with it?  In fact, could the thing have been done by a woman?

“Most persons,” remarked Craig, as he studied the marks on the door, “don’t know enough about jimmies.  Against them an ordinary door-lock or window-catch is no protection.  With a jimmy eighteen inches long, even an anemic burglar can exert a pressure sufficient to lift two tons.  Not one door-lock in ten thousand can stand this strain.  It’s like using a hammer to kill a fly.  Really, the only use of locks is to keep out sneak thieves and to compel the modern, scientific educated burglar to make a noise.  This fellow, however, was no sneak thief.”