Superintendent Merrington sat in his office at Scotland Yard, irascible with the exertions of a trying day which had made heavy inroads upon his temper and patience. He had several big cases on his hands, his time had been broken into by a series of visitors with grievances, and he had been called upon to adjust a vexatious claim of a woman attacked in the street by a police dog, while the animal was supposed to be on duty tracking a sacrilegious thief who had felled a priest in an oratory and bolted with the silver candlesticks from the altar.

The woman had gone mad from the shock and had been placed in a public asylum, where she had imagined herself to be a horse, and in that guise had neighed harmlessly, for some years, until cured by auto-suggestion by a rising young brain doctor who had devoted much time and study to her peculiar case. Her first act of returned reason was to bring a heavy claim for damages against Scotland Yard, and Merrington had fought it out that day with an avaricious lawyer who had taken up the case on the promise of an equal division of the spoils.

Merrington had preferred to pay rather than contest the suit in law, and he was exceedingly wroth in consequence. He was angry with the old woman for presuming to get cured, and angry with the brain doctor for curing her. He considered that the brain doctor had been guilty of a piece of meddlesome interference in restoring the old lady to so-called sanity in a world of fools, without achieving any object except robbery from the public funds by a rascally lawyer. To use Merrington's own words, expressed with intense exasperation to an astonished subordinate, the old woman was quite all right as a horse, comfortable and well-fed, and had probably got more out of life in that guise than she ever had as a human being, compelled to all sorts of shifts and contrivances and mean scrapings before her betters for a scanty living, with nothing but the work-house ahead of her. He concluded in a sort of grumbling epilogue that some people never knew when to leave well alone.

It was in no very amiable frame of mind, therefore, that he received Colwyn's card with a pencilled request for an immediate interview. Merrington disapproved of all private detectives as an unwarrantable usurpation of the functions of Scotland Yard, but he particularly disapproved of a private detective like Colwyn, whose popular renown was far greater than his own. But there were politic reasons for the extension of courtesy to him. The famous private detective was such a powerful rival that it was best to conciliate him with a little politeness, which cost nothing, and he had done Scotland Yard several good turns which at least demanded an outward show of gratitude. He had influence in the right quarter, too, and, altogether, was not a person to be lightly affronted. The consideration of these factors impelled Merrington to inform the waiting janitor that he would see Mr. Colwyn at once, and even caused him to crease his fat red features into a smile of welcome as he awaited his entrance.

When Colwyn appeared in the doorway the big man he had called to see got up from his swing-chair to shake hands with him. When his visitor was seated Merrington leaned back in his own chair and remarked, in his great rolling voice:

"What can I do for you, Mr. Colwyn?"

"Nothing personally. I have called to have a talk with you about the Heredith case."

The veneer of welcome disappeared from Merrington's face at this opening, though a large framed photograph of himself on the wall behind his chair continued to smile down at the private detective with unwonted amiability.

"Ah, yes, the Heredith case," he responded. "A strange affair, that. I investigated it personally. It was a pity you were not in it. There were points about that murder—distinct points. You would have enjoyed it."

Merrington's professional commiseration of Colwyn's ill-luck in missing an enjoyable murder was intended to convey a distinct rebuke to the other's presumption in discussing a case in which he had not been engaged. But Colwyn's next words startled Merrington out of his attitude of censorious dignity.

"I was not in the case at first, but I was called into it subsequently by the husband of the murdered woman. He is dissatisfied with the outcome. He thinks a mistake has been made in arresting the girl Hazel Rath."

The silence with which Merrington received this information was an involuntary tribute to his visitor, implying, as it did, that he knew Colwyn would not have come to see him without weighty reason for the support of what sounded like the repetition of a mere expression of opinion.

"I was reluctant to interfere until Mr. Heredith told me something which suggested that one of your men was in danger of underestimating an important clue," continued Colwyn. "That decided me. I went back with Mr. Heredith in my car the night before last. After my arrival at the moat-house I made an interesting discovery—quite by accident. I discovered that a pearl necklace which had been given to Mrs. Heredith by Sir Philip Heredith was missing from the jewel-case in which it had been locked. That jewel-case was in Mrs. Heredith's bedroom on the night she was murdered."

This piece of news was so unexpected that it caught Merrington off his guard.

"A jewel robbery as well as murder!" he ejaculated, in something like dismay.

"It looks like it. You will be able to form a better judgment when I have told you all the circumstances of the discovery."

Merrington had long ago convinced himself that the case he had worked up against Hazel Rath did not admit of the slightest possibility of doubt; and, like all obstinate men, he adhered to his convictions with additional strength in the face of anything tending to weaken them. As he recovered from his surprise at the private detective's piece of news, he listened to his account of the opening of the jewel-case with the wary air of one seeking a loop-hole in an unexpected obstacle. Before Colwyn had finished he had found it in the belief that Hazel Rath, and nobody else, had stolen the missing jewels.

"This girl is a thief as well as a murderer," was the manner in which he expressed his opinion when Colwyn had ceased speaking. "She has stolen the necklace."

"She may have done so, but it is too great an assumption to make without proof," returned Colwyn. "You must be perfectly well aware, Mr. Merrington, that this belated discovery is of the utmost importance to the Crown case, one way or the other. If you can prove that Hazel Rath stole the necklace, it gives you an unassailable case against her. If the necklace was stolen by somebody else, you are confronted with a new and strange aspect of this murder."

"Not to the extent of lessening the strength of the case against this girl," replied Merrington doggedly. "She was seen going to the staircase leading to Mrs. Heredith's room just before the murder; her brooch was found upstairs in the room; and the revolver and her handkerchief were found concealed in her mother's rooms. Add to that, her silence under accusation, and it is impossible to get away from the belief that she, and nobody else, murdered Mrs. Heredith."

"I am not attempting to controvert your theory or contradict your facts," rejoined Colwyn coldly. "My visit is to bring under your notice a fresh fact in the case which needs investigation. Whether that fact squares with your own theory or not, it is too important to be disregarded or overlooked. That is why I left the moat-house immediately I discovered it. I felt that you had been ignorantly misled, and that it was only right you should be told without delay."

Merrington was conscious of that evanescent feeling which men call gratitude. His impulse of thankfulness towards the man opposite him was all the keener for the realization that he would not have acted so generously if he had been in Colwyn's place. But his gratitude was speedily swallowed up by the knowledge that he had been led astray, and his anger was mingled with the determination to find a scapegoat.

"I am obliged to you for your information, although I do not attach quite so much importance to it as you do," was his careful rejoinder. "But I certainly blame Detective Caldew for not finding it out before you did. He made the original inquiries at the moat-house, and he seems to have made them very carelessly. He said nothing to the Chief Constable of Sussex or myself, when we arrived, about a jewel-case, locked or open."

"He didn't know himself."

"It was his duty to inquire. When he assured us, on the authority of Miss Heredith, that nothing was missing, I naturally assumed that he had made the proper inquiries. But I thank you for letting me know, and I shall, of course, have investigations made. But I should like to know why young Heredith interfered and brought you into the case?"

"For one thing, he has a strong belief in Hazel Rath's innocence."

"Mere sentiment," replied Merrington contemptuously. "Perhaps he's still sweet on the girl."

"There is more than that in it. There's the question of the revolver. Of course you are aware that he identified the revolver with which his wife was shot as the property of Captain Nepcote, a guest at the moat-house who left on the afternoon of the day on which Mrs. Heredith was murdered. Heredith does not accept your theory of the way in which Hazel Rath is supposed to have obtained the revolver. He does not think that Nepcote left the revolver behind him at the moat-house. He told Caldew this, but Caldew said the ownership of the revolver was a matter of no consequence."

"Caldew's a fool if he said that, and I wish I'd never allowed him to meddle in the case," replied Merrington forcibly. "I've had the police court proceedings against the girl put back for a week till the question of the ownership of the revolver could be settled. Now that it is decided I shall have Nepcote interviewed and questioned without delay."

"Before you try to trace the missing necklace?" The faint inflection of surprise in Colwyn's voice might have escaped a quicker ear than Merrington's.

"Scotland Yard will trace the necklace fast enough," he confidently declared. "I like to take things in their proper order. The next thing to do is to ascertain whether Nepcote left his revolver behind him at the moat-house, though I have not the least doubt that he did. The necklace is really a minor consideration. It merely provides another motive for the murder—cupidity as well as jealousy."

"Is that the way you regard it?" A less thick-skinned man than Merrington would this time have caught something more than surprise in the other's tone.

"Is there any other way of looking at it?"

"I would not like to venture an opinion in this case without more knowledge than I have at present," returned Colwyn in sober accents. "But so far as I have gone into it I should say that there are several things which seem to require more explanation. Nepcote's own actions seem to call for some investigation."

"You are surely not suggesting that Nepcote had anything to do with the murder or the robbery of the pearls?" said Merrington in an astonished voice. "That is quite impossible. He left the moat-house in the afternoon before the murder was committed, and went over to France that night."

"He didn't go to France that night. He stayed in London, and did not return to France until the following day."

Merrington was obviously startled at this unexpected information.

"This is news to me," he said gravely. "Where did you learn it?"

"From the War Office this morning. There is no possibility of mistake. Nepcote was in London on the night of the murder."

"He probably has an explanation, but what you have just told me is an additional reason for seeing and questioning Nepcote without delay, even if I have to send a man to France for the job."

"It will not be necessary for you to do that. Nepcote returned to London two days ago—sent over on some special mission. I ascertained that fact also from my friend at the War Office."

Merrington glanced at a small clock which stood on the desk in front of him.

"I will go immediately and see him myself," he said.

"I should like to accompany you."

"I shall be delighted to have you," replied Merrington with complete untruth. "I have Nepcote's address included in the list of guests who were at the moat-house at the time of the murder," he added, opening his pocket-book and hastily scanning it. "Ah, here it is—10 Sherryman Street. I'll send for a taxi-cab. Is there anything I can do for you in return for your kindness in bringing me this information?"

"I should be obliged if you would lend me a copy of the coroner's depositions in the Heredith case."

"With pleasure." Merrington touched a bell, and instructed the policeman who answered it to bring a typescript of the Heredith murder depositions and the revolver which figured as an exhibit in the case. "And tell somebody to call a taxi, Johnson," he added.

When Merrington and Colwyn emerged from the swing doors of the entrance a few moments later, a taxi-cab was waiting at the bottom of the stone steps, with a pockmarked driver leaning against the door of the vehicle, gazing moodily over the Thames Embankment. He received Merrington's instructions morosely, cranked his cab wearily, and was soon threading his way through the mazes of Trafalgar Square and Piccadilly Circus with a contemptuous disregard for traffic regulations, due to his prompt recognition of the fact that he was carrying a high official of Scotland Yard who was above rules of the road regulated by mere police constables. He skimmed in a hazardous way along Regent Street, dipped into the network of narrower streets which lay between that haunt of the fox and the geese and Baker Street, and finally stopped abruptly outside a tall house which was one of a row in a quiet street which led into the highly fashionable locality of Sherryman Square.

Sherryman Street, in which the taxi-cab had stopped, was an offshoot and snobbish mean relation of Sherryman Square, which housed a duke, an ex-prime minister, and a fugitive king, to say nothing of several lesser notabilities, such as a High Court Judge or two, several baronets, and a war-time profiteer whose brand-new peerage had descended in the last heavy downpour of kingly honours. Because of their proximity to these great ones of the earth, the inhabitants of Sherryman Street assumed all the airs of exclusiveness which distinguished the residents of the superior neighbourhood, and parasitical house agents spoke of it with great respect because one end opened into the rarefied atmosphere of the Square. It was true that the other end was close to a slum, and there was a mews across the way, but these were small drawbacks compared to the social advantages.

Sherryman Street was full of gaunt, narrow houses, with prim fronts and narrow railed windows, let in segments, flats, and bachelor apartments. Number 10 was as like its fellows as one drab soul resembles another. Superintendent Merrington's ring at the doorbell brought forth an elderly woman with an expressionless face surmounted by a frilled white cap. She informed them in an expressionless voice that Captain Nepcote's apartments were on the second floor. Having said this much, she disappeared into a small lobby room off the entrance hall, leaving them free to enter.

A knock at the entrance door of the second-floor flat brought forth a manservant whose smart bearing and precision of manner suggested military training. He cautiously informed Superintendent Merrington, in reply to his question, that he was not sure if Captain Nepcote was at home, but he would go and see.

"Who shall I say, sir?" he asked, in unconscious contradiction of his statement.

Merrington stopped further parleying by impatiently pushing past the servant into the room.

"Go and tell your master I want to see him," he said, seating himself.

The servant looked angrily at the burly figure on the slender chair, and then, as though realizing his inability to eject him, he left the room without further speech.

The room they had entered was furnished in a style which suggested that its occupier had sufficient means or credit to gratify his tastes, which obviously soared no higher than racehorses and chorus girls. Pictures of the former adorned the wall in oak; the latter smirked at the beholder from silver frames on small tables. The room was handsomely furnished in a masculine way, although there was the suggestion of a feminine touch in the vases on the mantelpiece and some clusters of flowers in a bowl.

The door opened to admit a young man, who advanced towards his visitors with a questioning glance. His appearance, though military, was far from suggesting the sordid warfare of the trenches. He was well-groomed and handsome, and wore his spotless uniform with that touch of distinction which khaki lends to some men.

"Good afternoon," he said, and waited for them to announce the object of their visit.

"Are you Captain Nepcote?" Merrington asked.

"My name is Nepcote," was the response. "May I ask who you are?" His glance included both his visitors.

"My name is Merrington," responded that officer, answering for himself. "Superintendent Merrington, of Scotland Yard. This is Mr. Colwyn, a private detective," he added, as an afterthought. "I wish to ask you a few questions. I understand you were staying at the residence of Sir Philip Heredith when young Mrs. Heredith was murdered."

"That is not quite accurate," replied the young man. "I left the moat-house on the afternoon of the day that the murder was committed, and returned to London. What is it you wish to ask me? I am afraid I cannot enlighten you about the crime in any way, for I know nothing whatever about it. It came as a great shock to me when I heard of it."

"Is this your revolver?" said Merrington, producing the weapon and laying it on the table.

"Why, yes, it is," said the young man, picking it up and looking at it in unmistakable surprise. "Where did you get it?"

"Where did you have it last?" was Merrington's cautious rejoinder.

"Let me think," returned Nepcote thoughtfully. "Oh, I remember. The last time I saw it was at the moat-house on the day before my departure. We were using it for a little target practice in the gun-room downstairs."

"And what did you do with it afterwards?"

"That I cannot tell you," responded Nepcote. "I have no recollection of seeing it since. I have never thought about it."

"Nor missed it?"

"No. It is no use to me—it is not an Army revolver. But it seems to me that I must have left it in the moat-house gun-room after the target shooting. After we finished shooting some of us had a game of bagatelle on a table in the gun-room. I must have put the revolver down and forgotten all about it afterward. I have no recollection of taking it upstairs, and I have certainly never seen it since. Was it found in the gun-room?"

"It was found at the moat-house, at any rate. It was the weapon with which Mrs. Heredith was killed."

"What!" His exclamation rang out in horror and incredulity. "Why, it is impossible. The thing is a mere toy."

"A pretty dangerous toy—as it turned out," was the grim comment of Merrington.

"It seems incredible to me," persisted the young man. "It's very old, and you have to be very strong with the finger and thumb to make it revolve. And the cartridges are very small; only seven millimetres—about a quarter of an inch. I've had the old thing for years, but I never regarded it as a real fire-arm. I'd never have let the girls use it in the gun-room if I'd thought it was a dangerous weapon. Perhaps there is some mistake."

"There is no mistake," replied Merrington. "Mrs. Heredith was killed with that revolver, and no other. We were unable to establish the identity of the weapon until a day or two ago, and that is one of my reasons for calling on you to-day—to make quite sure of the identity and see if you could tell me where you left it."

"I have no doubt now that I must have left it behind me at the moat-house," responded Nepcote. "I was recalled to France and went away in a hurry. God forgive me for my carelessness. To think that it resulted in this terrible murder!" His face had gone suddenly white.

"Did you return to France that night?" asked Merrington carelessly.

"As a matter of fact, I did not. When I returned to London from Sussex I found another telegram here from the War Office extending my leave until the following day. I returned to France the next afternoon."

"Thank you, Captain Nepcote." Merrington, as he rose to go, held out his hand. It was evident that the statement about the telegram had cleared his mind of any suspicions he may have felt about the young man. As Nepcote shook hands he added: "You had better hold yourself in readiness to attend the police court inquiry, which will be held a week from to-day. I will send you a proper notification of time and place. All we need from you is the formal identification of the revolver."

"Is it essential that I should attend?" asked the young man anxiously. "I'd rather not be mixed up in the case at all, you know. Besides, I may have to return to France."

"Perhaps we shall be able to dispense with your evidence now that we have the facts," replied Merrington, after a moment's consideration. "I will see what can be done, and let you know. You had better give me your address in France, in case you have left England. It is necessary for me to know that, because the case has to some extent taken a new turn by the discovery that robbery as well as murder has been committed. A valuable necklace belonging to the murdered woman is missing."

Captain Nepcote had taken out his pocket-book while Merrington was speaking, in order to extract a card. As the other uttered the last sentence, the pocket-book half slipped from his fingers, and several other cards fluttered onto the table. Nepcote picked them up hastily, but not before Colwyn's quick glance had taken in their contents. It seemed to him something more than a coincidence that the name and address displayed in neat black lettering on one of the cards should be identical with one of the Hatton Garden addresses given him by Musard at the moat-house the previous day.