"I think it very probable that information was obtained from Ewing," I said. "But it may have been given without any criminal intention. In my opinion the planning of the robbery must have begun before Ewing's dismissal. Besides, though I have failed to trace Ewing, I do not find anything against him beyond this matter of the petty cash. There are no debts worth mentioning, and no entanglements of any kind apparently."

"So we get no definite answer regarding him," said the professor; "we must, so to speak, put him aside for further consideration. Let us get back to the gang for a moment. That money would require a lot of moving, Wigan. a.s.suming Coulsdon to be honest, the door of the strong-room was intact at two o'clock on Sunday morning. The tell-tale clock is a witness to this, and seven hours later the alarm was given.

I do not say that a motor car might not have been loaded as you suggest and driven out of the city without attracting the notice of the police, but if you ask me whether it is likely I must decidedly answer in the negative."

"The fact remains that the gold was got away," I answered. "You cannot alter that."

"Our methods sometimes clash, Wigan. You make a theory to fit the facts; I get a theory first, and then look for facts to fit it. I grant yours is the more orthodox method; still, what is considered orthodox has sometimes been shown to be wrong; and as for facts--well, if I choose to think that this gold has not left the city, how can you convince me beyond all dispute that it has? You can't. You do not know. For instance, it might be concealed in this man Bowman's office.

Say you are able to prove that it isn't, there are still many other offices in the building where it might be hidden, ready to be got rid of gradually. At this stage of the inquiry, at any rate, we are not prepared to guarantee the honesty of all the firms in the block of buildings adjoining the bank."

"So that is your theory?" I said, somewhat impressed by it, I admit.

"No, it isn't," said Quarles. "I was merely showing how unstable was your central fact. No, my theory is quite different."

"May I hear what it is?"

"I agree with Zena. Continue to hunt for Frederick Ewing. Get a dozen men on to the business, if you like. Instruct them to pick up the most trivial items of information concerning him. Run his companions to earth, find out all about his debts, however small they may be; that's the line along which you are likely to pick up the clew. If you can manage to put another detective on the job with you, I am a candidate for the post. I should like to see the strong-rooms and the window, and to ask a few questions."

My suggestion that Christopher Quarles should be a.s.sociated with me in the inquiry met with some opposition. The officials of the bank seemed a little nervous of too much publicity. The fact of the robbery, quite apart from the actual loss, had injured the bank considerably.

However, all objections were overruled.

When Quarles and I went to the bank, we were requested to walk in and see Mr. Wickstead, who was one of the three general managers, and he very graciously apologized to the professor for the difficulties which had been raised.

"I need not tell you that this is a very serious business for us," he said. "The loss, large as it is, const.i.tutes the least part of the damage. Clients, naturally enough, are anxious about the security of their own property, and already some nervous persons have removed their deed boxes."

"I can quite see the necessity of precaution," said Quarles. "You may rely on my discretion. May I ask whether the full amount of the loss has yet been ascertained?"

"Yes, I think we have now got to the bottom of it."

"The securities--deeds, bonds, and such-like--have they been tampered with?"

"No."

"The gang must have possessed wonderful knowledge," said Quarles.

"Marvelous."

"May I take it, Mr. Wickstead, that there is no suspicion of collusion with officials in the bank?"

"You may. Of course, you are aware that we had to dismiss a clerk recently?"

"Yes, who cannot be found. I understand that he would be in a position to give the necessary information if he chose to do so?"

"That is true. He was in a position of some importance."

"With regard to this gold reserve, how often is it examined?" asked Quarles.

"At intervals, not regular intervals. The unexpected inspection is generally considered the best. We have a staff of inspectors for this purpose."

"My point is this," said Quarles; "might the robbery of this gold extend over a period of time, several weeks, let us say--a bag taken to-day, for instance, replaced by a dummy one, perhaps, and another bag taken in three days' time, and so on?"

Mr. Wickstead smiled.

"This reserve is kept in an inner strong-room. Three keys are necessary to open the door, and these three keys are kept by three different persons. I have one. Three of us have to go together to open that inner room."

"Ewing would never be there alone, then?"

"Certainly not," Wickstead answered. "For my part, I do not believe Frederick Ewing had anything to do with the affair at all. The circ.u.mstances of his dismissal naturally make him suspect, but I think that offense was the beginning and end of his dishonesty."

"Yet he has disappeared," said Quarles, "and it looks as if he had taken extreme care to leave no clew behind him."

"He would feel the disgrace keenly, I imagine, and would wish to efface himself," the general manager returned.

"There was no question of prosecuting him, I suppose?"

"One of the directors suggested that course, but it was decided not to do so."

"Could Ewing possibly have heard that a prosecution was contemplated?"

asked Quarles. "That would account for his complete disappearance."

"He certainly could not have heard of it. I am sorry for Ewing; indeed, I tried to get the directors to reconsider their decision and give him another chance. It is a terrible thing for a man to have to face poverty and degradation like that. All I achieved was to get laughed at for my sentimentality."

"Then you would still trust Ewing?"

"I would," Mr. Wickstead answered with deliberation.

Quarles and I then went to examine the strong-rooms, which were empty now, the securities having been removed to other rooms.

A constable was on duty in the pa.s.sage leading to them, and materials lying about showed that the work of fitting new doors was to commence at once. Quarles put on a particularly heavy pair of spectacles and produced a high-power pocket lens as well. He examined the locks and hinges of the ruined doors, and the various bolts which were thrown by the action of the turning keys. He carefully scanned the marks and the ruin which the explosion had made, and also the steel-bound holes into which the bolts fitted when the doors were fastened. Both the inner and the outer strong-rooms were examined with the same close scrutiny, and I pointed out to him the spot where the porter, Coulsdon, had been found, and where the rifled deed boxes had stood.

"Had the boxes been blown open?"

"No; forced open," I answered.

"I am not sure what explosive was used upon the doors, Wigan--gelignite or some similar preparation, I suppose--but it was powerful and peculiar in its action. How about finger-prints?"

"There were none on the doors. Either the explosion destroyed all trace or the men wore gloves."

"I suppose men of an expert gang would take that precaution?"

"They would be likely to think of everything."

"Yes; but since the gang is entirely unknown at Scotland Yard, that might be considered an unnecessary precaution, eh?"

He turned his attention to the ruined doors of the inner room again, picking out minute pieces of debris from the lock with a pair of tiny forceps, and examining the pieces under the lens.

"I cannot be certain what explosive was used, Wigan, and the light here is bad. I will examine some of this dust at home," and he emptied the contents of the palm of his hand into a small envelope, which he folded up carefully and placed in an inner pocket.

Then he examined the floor of the outer room, and the pa.s.sage without, picking up several bits of rubbish, but finding nothing of interest.