Eustace had disappeared as completely and mysteriously as the gold which had been in his keeping.

Every corner of the building from the roof to the basement was examined. Even the cupboards were inspected and the made-up beds pulled to pieces, lest he should have succeeded in secreting himself amongst the jam-pots or inside the covering of a pillow; but no trace of him could be found.

His hats hung on their accustomed pegs, so that if he had gone from the house he must have gone bareheaded. But the question which none could answer was how he had managed to go from the house at all.

At the time Mrs. Burke left the dining-room, Brennan was standing talking to Gale and Johnson in front of the private entrance. In the office Harding was waiting for his manager to come from the house. Thus two out of the three ordinary means of exit could not have been used without Eustace being seen. The third was the back door opening from the scullery, which, in turn, opened from the kitchen. Bessie was in the kitchen when the slamming of the dining-room door announced the departure of Mrs. Burke.

Both she and her mistress were insistent that Eustace did not pass through the kitchen. Each told the same story when interrogated. As soon as the signal of Mrs. Burke's departure was heard, Mrs. Eustace went to the door leading from the kitchen to the passage and stood waiting for her husband to appear. When he did not do so, she went to the door of the office, knocked, and asked Harding if Eustace were there. She maintained that the door of the dining-room had not been opened after Mrs. Burke flounced out. Harding, who was listening in the office, also maintained it had not been opened.

The mystery of Eustace's disappearance was still agitating everyone when Sub-Inspector Durham rode up to the bank. Listening, without comment, to all Brennan had to report, he went through the premises with Harding and Brennan, saying nothing till he came to the back door.

Situated as it was, with only the bush behind and beyond it, the bank was thus free from being overlooked. A block of ground at the back was surrounded by a three-rail fence, but the cultivation was limited, a score of fowls occupying the far end and the remainder of the area consisting of a grass patch and a few indigenous shrubs left when the ground was fenced in from the bush.

Standing there, he waved his arm comprehensively towards the unoccupied land at the side and back of the building.

"Once outside, who was to see him clamber over that fence and make for the shelter of the bush?" he asked. "While you were loitering at the front door, Brennan, your man was walking out at the back."

Brennan gnawed his moustache in chagrin.

"But—how did he get out of the dining-room?" Harding exclaimed.

Durham turned slowly and looked steadily into Harding's eyes.

"He walked out, Mr. Harding, walked out through the door."

"The door was shut."

"When you saw it. It was probably closed as noiselessly as it was opened—his wife saw to that. Then, as soon as he had slipped out this way, she came to your office and threw dust in your eyes by asking where her husband was. Just the sort of thing a woman would do. What did he do with his keys—the bank keys, I mean?"

"He had them with him."

"Oh, no, Mr. Harding. They would be no further use to him. He must have left them behind him. We shall find them somewhere. Let me have a look at the safes which were robbed."

"Shall I send off a description of the man to the police in the neighbourhood, sir?" Brennan asked.

"Did you not do so at once?" Durham asked, swinging round sharply.

"I was preparing it when you arrived, sir."

"We will look at the safes," Durham said.

Harding had pushed-to the doors of the big safe As he pulled them open Durham pointed.

"What keys are those?" he asked.

In the lock of the reserve recess the keys Eustace gave Harding in the morning were still hanging. Harding took them out.

"They are the manager's keys," he said. "In the excitement of the discovery that all the gold had gone, I must have forgotten to return them. I had no idea they were here when you asked me what Eustace had done with the keys. I entirely forgot them."

"But he did not, Mr. Harding. Do you know where he kept his private papers?"

"That was his private office," Harding replied, pointing to the little ante-room.

"When do you expect the relieving officer to arrive?"

"I can hardly say. He may come by train to the junction, in which case he should be here about noon to-morrow."

"Then you will be in charge until he arrives?"

"I have telegraphed to the head office reporting that Eustace has disappeared and asking for instructions. Until they come, of course, I am in charge."

"Then you will come with me while I examine his desk, though I do not suppose it contains anything but official papers—now. In the meantime, Brennan, send away your description to all the neighbouring police-stations and also to head-quarters for general distribution. When you have done that you can come back here. I shall be waiting for you."

He followed Harding into the little room.

"You had better go through the papers, Mr. Harding. They will probably all relate to the bank's business. I only want to see those which do not."

"It was in this drawer he kept his own papers," Harding said, as he touched the knob of one of the side drawers.

"Is it locked?"

"No," Harding replied, as he pulled it out. "But it is empty," he added.

"Quite so," Durham replied in an unconcerned voice. "As I expected."

Harding stared at him in perplexity.

"But—but——" he stammered. "I don't understand it. I cannot—I cannot believe it of him."

Durham stood silent.

"Only a madman would have done such a thing, and Eustace is no more mad than I am," Harding added.

Still Durham said nothing.

"But if he had done such a thing, why did he remain here? Why not get away at the same time as he got the gold away? Surely——"

"Would you mind looking through the remainder of the drawers?" Durham interrupted.

Harding opened them one after the other, examined the papers they contained, and replaced them without making any further remark. The search was unavailing so far as private papers were concerned—all were connected with the bank. As Harding examined them, Durham stood beside the table without a word or a glance at the papers. When the last drawer had been opened, gone through, and closed, Harding turned to him.

"There is nothing here except what concerns the bank," he said.

"You are sure he kept all his own papers here?"

"Quite sure. The first drawer I opened was full of them yesterday. He had it out after the bank closed last night when I came in to give him the cash balance."

"I will see Mrs. Eustace," Durham said shortly. "In the interests of the bank I should like you to be present. Will you ask her to come in here?"

"Perhaps she would rather see you in the house."

"As she pleases—if you will ask her."

Harding found her sitting disconsolately in the dining-room and gave her Durham's message.

"Very well, I'll see him—here—if you stay."

She spoke without moving her eyes.

"I will be here," he said as he left the room to call Durham.

In the office he found a telegram had just arrived. It was an answer to his wire to the head office.

He handed the message to Durham, who just glanced at it.

"Is she coming in here or not?" Durham asked.

"She is in the dining-room, and will see you there," Harding answered.

Mrs. Eustace was standing staring out of the window when they entered the room.

"I can tell you nothing. I know nothing more than I have already said," she exclaimed as she turned to meet them.

"If you will kindly answer my questions I will be obliged," Durham replied. "Can you tell me where your husband kept his private papers?"

"Yes, in his office—that is, as a rule."

"And when he did not keep them there, where were they?"

"Oh, he always kept them there, but sometimes he had some in his pocket. Last night——"

"Yes? Last night——?" Durham said as she stopped.

"Oh, it's nothing. Merely that he had some papers in his pocket and discovered they were there when he was upstairs."

"Do you know what he did with them?"

"Of course I do. He left them on the dressing-table. They are there now."

"Will you show them to me?"

"Mr. Harding, will you take him upstairs? The papers are by the looking-glass."

Durham followed Harding upstairs without a word. On the dressing-table a small packet of folded documents was pushed half under the mirror. Durham picked them up and glanced at them.

"Thank you," he said. "Now we will go down again."

"These are the papers you referred to?" he asked, as soon as they were in the dining-room.

"Yes," Mrs. Eustace answered.

Durham laid them on the table in front of him.

"Can you tell me anything about your husband's private affairs?" he asked, looking steadily at her.

"I don't quite understand what you mean," she replied slowly.

"In regard to his mining speculations."

Harding saw the momentary start, quickly recovered, that she gave at the question.

"Do you know he speculated?"

She sat silent with averted face.

"Do you know he speculated both in shares and horse-racing?"

Still there was no reply, and Durham added, "Speculated and lost—heavily?"

"Not heavily," she exclaimed, flashing round upon him. "He did not lose heavily. He may have——"

She checked her words suddenly, closing her lips and turning her face away.

"Will you please finish your sentence, Mrs. Eustace?"

"He may have lost—sometimes; but he won as well. He had those shares—they may yet bring him in a fortune," she said, pointing to the papers on the table.

"Do you know if there was ever any official reference to his speculations?"

Harding could barely hear the words as, with bowed head, Mrs. Eustace replied.

"I did not quite catch your answer," Durham said quietly.

"I said yes, there was—once."

"Did he tell you what was said?"

"I don't know," she said after a few moments' silence. "You had better ask the bank. I don't know anything about it."

"Perhaps you know why your husband was appointed to this branch?"

"I don't know anything about it," she replied in a low tone.

"It may save time if I tell you at once, Mrs. Eustace, that the general manager of the bank has put me in possession of all information regarding your husband—you will not improve the situation by denying what I know you thoroughly understand."

Mrs. Eustace looked up and met a glance which gave her the uncomfortable sensation of being looked through and through. She lowered her eyes more quickly than she had raised them, paled and then flushed blood-red.

"Your husband did not escape through the kitchen," Durham said in his even tone of voice.

"I have already said so," Mrs. Eustace replied, scarcely above a whisper.

"He left this room by the window."

The blood left her cheeks as she started. Harding saw her hands clasp tightly.

"And you secured the window on the inside after he had gone."

"No!"

The monosyllable escaped her lips like the yap of a dog at bay.

"You secured the window on the inside after he had gone," Durham repeated in cold, unruffled tones.

Mrs. Eustace sprang to her feet and faced him.

"It's a lie," she cried. "The room was empty when I came to it."

"The room was empty, quite so. And the window was open. You closed and secured it."

"I tell you I did not."

"You have already said that you only stood at the kitchen door until you went to the office to ask whether your husband was there. Now you say the room was empty when you came to it. Which statement do you expect me to believe?"

"I don't care what you believe," she cried. "You have no right to ask me these questions. I will not answer you. Mr. Harding, I appeal to you. If you have no regard for the honour of an absent friend, at least you might protect the wife of your friend from insult."

Durham's eyes never wavered as he watched her.

"No insult is offered or intended, Mrs. Eustace," he said quietly. "Mr. Harding, in the interests of the bank, as well as in the interests of your husband, is desirous, as we all are, of knowing the truth. I will ask you one more question: Where were you when Mrs. Burke left the dining-room and crossed the passage to the front door?"

Mrs. Eustace, with close-set lips, stood defiantly silent.

"Will you answer that question?" Durham said.

"No, I will not. I will tolerate this no longer."

With a quick, angry gesture she turned to the door.

Durham was on his feet and in front of her before she could take two steps.

"Until I have seen your servant, Mrs. Eustace, you will remain here," he said. "Will you kindly come with me, Mr. Harding?"

He held the door open while Harding passed out, following him without another word.

But there was little to be ascertained from Bessie more than she had already told. She heard the door slam and her mistress go to the kitchen door, but whether she went on to the dining-room or not, Bessie "didn't notice."

"Could you see out of the window at the time?" Durham asked.

"No, sir, I was in the scullery washing up," the girl replied.

Mrs. Eustace, much to Harding's surprise, was still in the dining-room on their return. The papers Durham had placed on the table were untouched.

"I am sorry to have had to detain you, Mrs. Eustace. For the present I have nothing further to ask you. These papers you had better take—I have no doubt they were left for you."

"What do you mean—left for me?" she exclaimed.

"A woman of your quick intelligence, Mrs. Eustace, scarcely needs to be told," he answered, adding, as he turned to Harding, "I would like a few moments with you in the office."

In the little ante-room that Eustace had used as his private office, Durham turned the searchlight of his questions upon Harding.

"Have you known Mr. Eustace for very long?"

"I have only known him personally since I came to this branch a few weeks ago."

"Did you apply to be sent here?"

"No. I knew nothing about it until I received instructions to come."

"Did you know Mrs. Eustace before you came here?"

"Not as Mrs. Eustace."

"You knew her before she was married?"

"Yes."

"Well?"

"Yes."

"Am I right in saying that you knew her very well?"

"Yes, I did know her very well."

"Don't think I am attempting to pry into your private affairs, Mr. Harding. In a case of this kind, the clues that lead to the unravelling of the mystery often lie on the surface in some trifling circumstance that seemingly has nothing whatever to do with the main question. You have already realised, I take it, that we are concerned with something quite distinct from the ordinary class of crime. Perhaps you have not had sufficient experience with the criminal class to recognise what was apparent to me from the beginning, that in this matter we are following the work of one who is a master of his craft."

"So far as that goes, I am absolutely dazed," Harding exclaimed. "The more I hear, the more hopelessly confused I grow."

"I am not surprised. You are following the work of someone who is, I am quite satisfied, no ordinary criminal, but one of the most astute, clever and unscrupulous individuals who ever adopted dishonesty as a profession. If I ask you questions which appear to you to be irrelevant and possibly impertinent, will you give me credit for being actuated only by my sense of duty, and answer those questions as fully and as accurately as you can?"

"Certainly," Harding replied.

"Thank you. Now, will you tell me this—Were you ever engaged to Mrs. Eustace before she married her present husband?"

"Yes."

"Did she break it off, or did you?"

"She—she married."

"She married Eustace, while she was practically engaged to you?"

"While she was actually engaged to me."

"Then he must have known of your existence?"

"I assume so, but—well, nothing was ever said about it between us. I will tell you exactly what happened. The letters I had written to her, the presents I had given her, and her engagement ring, were returned to me in a packet through the post with a piece of wedding-cake. Until I came here and met her, I did not know to whom she was married. Whether Eustace knew we had once been engaged I do not know. I never referred to it."

"You never knew that, in applying for an assistant, he named you personally to the general manager of the bank and gave as a reason a long-standing friendship?"

The look of astonishment which showed on Harding's face was sufficient answer.

"Yet it is what happened—I have the information from your general manager."