Colwyn spent a couple of hours that night reading the depositions he had obtained from Merrington, and next morning he studied them afresh with a concentration which the incessant hum of London traffic outside was powerless to disturb. He was well aware that a report was a poor substitute for original impressions, but in the typewritten document before him lay the facts of the Heredith case so far as they were known. It was a clear and colourless transcription of the narrative of the witnesses, set down with a painstaking regard for the value of departmental records, and chiefly valuable to Colwyn because it contained the expert evidence which sometimes reveals, with the pitiless accuracy of science, what human nature endeavours to hide. In the balance of the scales of justice it is the ascertained truth which weighs heavier than faith, reason, or revealed religion.

When he had finished his study of the depositions, he sat awhile pondering over his own discoveries since he had been called into the case by the husband of the dead woman. These discoveries, due apparently to chance, invested the murder with a complexity which stimulated all the penetrative and analytical powers of his fine mind, because they brought with them the realization that he was face to face with one of those rare crimes where the solution has to be unravelled from a tangle of false circumstances, which, by their seeming plausibility, make the task of reaching the truth one of peculiar difficulty. As Colwyn sat motionless, with his chin resting on his hand, brooding over the sullen secretive surface of this dark mystery, the feeling grew upon him that the murder had been preconceived with the utmost cunning and caution, and that the facts so far brought to light, including his own discoveries, did not penetrate to the real design.

The one conviction in his mind at that moment was that the man he and Merrington had interviewed on the previous afternoon had some connection with the mystery, and that an investigation of Nepcote's actions was the first step towards the solution of the murder. Colwyn based that belief on the apparently detached facts of the revolver, the patch of khaki he had found in the woods near the moat-house, and the accident which disclosed that Nepcote was carrying the address of a Hatton Garden jeweller in his pocket-book. These things, taken apart, had perhaps but slight significance, but, considered as links in a chain of events which started in Philip Heredith's statement that he had first met his wife at a friend's house where Nepcote was also a guest, and finishing with the knowledge that Nepcote had not returned to France on the night of the murder, they assumed a significance which at least warranted the closest investigation.

Colwyn was not affected by the fact that Superintendent Merrington looked at the case from an entirely different point of view. He did not want the help of Scotland Yard in solving the crime. He had too much contempt for the official mind in any capacity to think that assistance from such a source could be of value to him. He always preferred to work alone and unaided. It was the Anglo-Saxon instinct of fair play which had prompted him to tell Merrington about the missing necklace, so that there might be no unfair advantage between them. Merrington had received the information with the imperviable dogmatism of the official mind, strong in the belief in its own infallibility, resentful of advice or suggestion as an attempt to weaken its dignity. It seemed to Colwyn that not only had Merrington's ruffled dignity led his judgment astray in an attempt to fit the discovery of the missing necklace into his own theory of the case, but it had caused him to commit a grave mistake in putting Nepcote on his guard at a moment when the utmost circumspection of investigation was necessary.

To Colwyn, at all events, the discovery of the missing necklace was of the utmost importance because it substituted another motive for the murder, and a motive which carried with it the additional complication that the thief had some motive in trying to keep its disappearance secret as long as possible by locking the jewel-case after the jewels had been abstracted. If Hazel Rath had not stolen the necklace, the whole of the facts took on new values. It was quite true that the mystery of Hazel Rath's actions on the night of the murder, her subsequent silence after the recovery of the brooch and the handkerchief and the revolver in her mother's rooms, remained as suspicious as before, but the changed motive caused these points to assume a different complexion, even to the extent of suggesting that she might be a lesser participant in the crime, perhaps keeping silence in order to shield the greater criminal.

Merrington, stiff-necked in his officialism, had been unable to see this changed aspect of the case, and, strong in his presumption of the girl's guilt, had acted with impulsive indiscretion in going to see Nepcote before attempting to trace the missing necklace.

Colwyn's reflections were interrupted by the appearance of the porter from downstairs to announce a visitor. The visitor, partly obscured behind the burly frame of the porter in the doorway, was Detective Caldew, of Scotland Yard. Colwyn had met him at various times, and invited him to enter. As Colwyn had once said, his feelings towards all the members of the regular detective force were invariably friendly; it was not their fault, but the fault of human nature, that they were sometimes jealous of him. So he made Caldew welcome, and offered him a cigar.

Caldew accepted the cigar and the proffered seat a little nervously. His was the type of temperament which is overawed in the presence of a more successful practitioner in the same line of business. He had long envied Colwyn his dazzling successes, but at the same time he had sufficient intelligence to understand that many of those successes stood in a class which he could never hope to attain.

At the present moment, Caldew's feelings were divided between resentment at Colwyn's action in conveying information to Scotland Yard which had earned him a reprimand from Superintendent Merrington, and the anxious desire to ascertain what the famous private detective thought of the Heredith case.

"Merrington has sent me round for the copy of the depositions he lent you yesterday." It was thus he announced the object of his visit. "Have you finished with it?"

It was apparent from this statement that Superintendent Merrington's gratitude for information received might now be considered as past history. Colwyn, reflecting that it had lasted as long as that feeling usually does, congratulated himself on his forethought in having made a copy of the report. He handed the copy before him to his visitor.

"I am obliged for the loan of it," he said. "It makes interesting reading. You're own share in the original investigations has some excellent touches, if you'll permit me to say so. That trap for the owner of the brooch was a neat idea."

Caldew's resentment waned under this compliment to his professional skill.

"The trick would have worked, too, if I hadn't been called downstairs," he said. "The girl was quick enough to get into the room while I was out of it. Not that it mattered much, as things turned out, but it is a strange thing about this necklace, isn't it?"

"Very. Has Merrington told you all about it?"

"Yes, and he gave me a rare wigging for not discovering the loss. Between ourselves, I do not think that I was treated quite fairly about it. Miss Heredith never said a word to me about a jewel-case being in the room. She took it downstairs before I arrived, and never mentioned it when I asked her if anything had been stolen. If she had told me I should have had the case opened. But that didn't weigh with Merrington. He's beastly unfair, and never loses a chance to put the blame on to somebody else when anything goes wrong."

"I am sorry if you got into trouble through my action in informing him," said Colwyn. "But of course you must realize that a discovery of such importance could not be kept secret."

"That's quite true," replied Caldew, in a softened voice. "Fortunately, it does not affect the issue, one way or another. Mr. Heredith believes that Hazel Rath is innocent, and I suppose that is why he has called you into the case. But she is guilty, right enough. I tried to make that clear to Mr. Heredith, but he appears to be a man of fixed ideas. The question is, what has become of the necklace? My own impression is that she has hidden it somewhere. She had no opportunity to dispose of it before she was arrested."

"That means that you think she has stolen it."

"Why, of course—" Caldew's confident tone died away at the expression of his companion's face. "Don't you?"

"I do not."

"Why not?"

"For one thing, the jewel-case was locked. How did the girl know where the key was kept?"

"She might have got the knowledge from her mother. Mrs. Rath, as the housekeeper, would probably know all about the keys of the household."

"Of the ordinary keys—yes. But that knowledge was hardly likely to extend to Mrs. Heredith's private keys, unless Miss Heredith told her. Even if Hazel Rath did know where the key was kept, it is difficult to believe that she searched for it after committing the murder, and then restored it to the drawer where it was kept. That argues too much cold-blooded deliberation even in a murderer, and more especially when the murderer is supposed to be a young girl."

"I am not so sure of that," responded Caldew, with a shake of the head. "Murder is a cold-blooded crime."

"On the contrary, murders are almost invariably committed under the influence of the strongest excitement, even when the incentive is gain, and the murder has been deeply premeditated. That is a remarkable truth in the psychology of murder. But the important fact about the theft of the necklace is that even if Hazel Rath knew where the key of the jewel-case was kept she had not time to obtain it from the drawer on the other side of the bed, steal the necklace, restore the key to its place, and escape from the room before the guests from downstairs entered the bedroom. If Hazel Rath was indeed the murderess, time was of paramount importance to her. She must have realized that the scream of her victim would alarm the household downstairs, and that some of the men must have started upstairs before the subsequent shot was fired."

Caldew was silent for a space, cogitating over these points with a troubled look which contrasted with his previous confident expressions of opinion about the case. His inward perturbation was made manifest in the question:

"Do you also share Mr. Heredith's view that Hazel Rath is innocent?"

"I cannot say. The facts against her are very strong."

"Of course they are strong!" exclaimed Caldew eagerly, as though clutching this guarded expression of opinion as a buoy for his own sinking conviction. "They are so strong that it is quite certain she committed the murder."

Colwyn remained silent. A statement which was merely an expression of opinion did not call for words.

Caldew, always impressionable, became uneasy under his companion's silence, and that uneasiness was tinctured in his mind with such a dread of the possibility of mistake that it flowed forth in impulsive words:

"I wish you would tell me what you really think of the case, Mr. Colwyn. I have been waiting for years for the chance of handling a big murder like this, and now that it has come my way I should like to pull it off. It means a lot to me," he added simply.

Colwyn reflected that he had already given away more information about the Heredith case than his judgment approved or his conscience dictated. But his kindly nature prompted him to help the anxious young man seated in front of him, who had so much more than he to gain by success.

"I think there is more in this case than you and Merrington have yet brought to light," he said.

"I suppose there is, if it is proved that Hazel Rath did not steal the necklace. But have you found out anything else besides the loss of the necklace?"

Colwyn did not directly reply. He was glancing over the depositions again.

"There are one or two curious points here," he remarked, as he turned over the leaves. "In the first place, the ammunition expert who was called at the inquest to give evidence about the bullet extracted from the body testified that in weight and in length it corresponded with the seven millimetre bullet made for a pinfire revolver. The bullet had undoubtedly been fired from the revolver which you found in Mrs. Rath's rooms. Bullets for English revolvers are not graded in millimetres, but there appears to be sufficient demand for this size to cause British firms to manufacture them. The nearest size in central-fire cartridge to seven millimetres is called the 300, which is .3 of an inch. Seven millimetres is .276 of an inch. The point to which I want to draw your attention is the extreme slightness and smallness of the revolver with which Mrs. Heredith was killed. As Captain Nepcote told Merrington yesterday, it is little more than a toy."

"That struck me as soon as I saw it," said Caldew. "But I do not see what bearing the fact has on the case, one way or another."

"Nevertheless, it is a point not without importance, when it is considered in conjunction with the other circumstances of the case. The evidence of the Government pathologist is also of interest. After stating the cause of death to be heart failure due to hÆmorrhage consequent upon the passage of the bullet through the lung, he mentions that there was a large scorched hole through the rest-gown and undergarment which Mrs. Heredith was wearing at the time she was murdered."

"I noticed that when I was examining the body."

"Was the dress-stuff smouldering when you saw the body?"

"No; but there was a smell of a burning fabric in the room."

"The Government pathologist says that the burnt hole was nearly two inches across, but he also states that the punctured wound made by the bullet was about the size of a threepenny piece. The disparity suggests two facts. In the first place, the shot must have been fired at very close range—very close indeed, considering the smallness of the revolver and the largeness of the burnt hole. In the next place, somebody must have extinguished the burning fabric before you arrived, otherwise it would have smouldered in an ever-widening ring until the whole of the dead woman's garments were destroyed."

"Mrs. Heredith may have extinguished it herself in her dying moments," said Caldew, who had been following his companion's deductions with the closest attention.

"That is unlikely, in view of the nature of her injuries. The bullet, after traversing the left lung, lodged in the spinal column. After such a wound Mrs. Heredith was not likely to be conscious of her actions."

"It may have been extinguished by Musard, who tried to stop the flow of blood while Mrs. Heredith was dying."

"He would have mentioned it to you. It is my intention to ask him, but my own opinion is that we are faced with a different explanation."

"What is that?"

"The presence of another person in the room."

"Somebody who escaped through the window!" exclaimed Caldew, placing his own interpretation on the deduction. "Do you suspect anybody?"

"Not exactly. But I intend to investigate Captain Nepcote's actions on the night of the murder."

Caldew, who lacked some of the information possessed by his companion, found this jump too great for his mind to follow.

"For what purpose?" he asked. "Nepcote returned to France before the murder was committed."

"He did not. He stayed in London that night, and did not return to France until the following day. He explained that yesterday by stating that when he reached London after leaving the moat-house he found another telegram from the War Office extending his leave for twenty-four hours."

"Merrington said nothing of this to me. All he told me was that you and he had seen Nepcote, who identified the revolver as his property, and said that he had left it behind at the moat-house by accident."

"Merrington is a man of fixed ideas, to use your phrase. He insisted on trying to fit in the loss of the necklace with his own theory of Hazel Rath's guilt. It was his obstinacy which led him to commit the folly of going to see Captain Nepcote before endeavouring to trace the missing necklace. It is only fair to Nepcote to add that he volunteered the information that he did not return to France on the night of the murder."

"That does not seem like the action of a man with anything to hide," commented Caldew thoughtfully.

"Unless he was facing a dangerous situation. In that case, frankness would be his best course to remove Merrington's suspicions. The fact that the murder was committed with his revolver is in itself a suspicious circumstance, in spite of the apparently plausible explanation. I have realized that all along. I had also previously acquainted Merrington with the fact that Nepcote did not return to France on the night of the murder, as was supposed. Merrington led up to that point skilfully enough, but it struck me that Nepcote saw the trap, and took the boldest course. It gave him time, at all events."

"Time for what?"

"Time to profit by Merrington's folly in putting him on his guard. Time to permit him to make his escape, if he is actually implicated in the crime."

"Surely you are reading too much into this," exclaimed Caldew in a protesting voice. "Nepcote's story seems to me quite consistent with what we know of his movements. Miss Heredith, when giving us the names of the guests who had been staying at the moat-house, mentioned that Captain Nepcote had been recalled to France on the afternoon of the murder by a telegram from the War Office. Nepcote tells you that when he reached London he found another telegram awaiting him extending his leave. Surely that is consistent?"

"Is it consistent that the two telegrams were sent to different addresses? They would have been either both sent to the moat-house, or both sent to his London flat—that is, if they were sent by the War Office. Only a relative or a personal friend would take the trouble to send to different addresses. There lies the weak point of Nepcote's statement."

"By Jove, there is a point in that," said Caldew, in a startled tone. "But these are facts which can be ascertained," he added, as though seeking to reassure himself.

"They can be ascertained too late. I have already set inquiries on foot, but it takes some time to gain any information about official telegrams. Nepcote has plenty of time to take advantage of Merrington's blunder, if there is any occasion for him to do so. No matter what his explanation is, the fact remains that he was in England, and not in France, on the night the murder was committed, and I propose to find out how he spent the time. But it is of the first importance to find out what has become of the missing necklace, which is the really important clue. Is Scotland Yard making any investigations about it?"

"Yes. Merrington has put me on to that because I let you score the point over him of discovering that it was missing. I am sure that he hopes I will fall down over the job of tracing it. I shouldn't be surprised if I did, too. It's no easy thing to get on the track of missing jewellery, especially if it has been hidden. I have not even got a description of the necklace to help me."

"I can give you a description, and perhaps help you in the work of tracing it."

"Can you? That's awfully good of you." Caldew's face showed that he meant his words. "Have you any idea where it is?"

"I have at least something to guide me in commencing the search—something, which, curiously enough, I owe to Merrington's blunder in visiting Nepcote before he looked for the necklace. We will go across to Hatton Garden, and I will put my idea to the test."