It was late afternoon when Colwyn reached Heredith the following day. The brief English summer, dying under the intolerable doom of evanescence for all things beautiful, presented the spectacle of creeping decay in a hectic flare of russet and crimson, like a withered woman striving to stave off the inevitable with pitiful dyes and rouge.

In this scene the moat-house was in perfect harmony, attuned by its own decrepitude to the general dissolution of its surroundings. Its aspect was a shuttered front of sightlessness, a brick and stone blindness to the changes of the seasons and the futility of existence. The terraced gardens had put on the death tints of autumn, but the house showed an aged indifference to the tricks of enslaved nature at the bidding of creation.

Colwyn's ring at the door was answered by Milly Saker, whose rustic stare at the sight of him was followed by an equally broad grin of recognition. She ushered him into the hall, and went in search of Miss Heredith. In a moment or two Miss Heredith appeared. She looked worn and ill, but she greeted Colwyn with a gracious smile and a firm handshake, and took him to the library. Refreshments were brought in, and while Colwyn sipped a glass of wine his hostess uttered the opening conversational commonplaces of an English lady. Had he a pleasant journey down? The roads were very good for motoring at that time of year, and the country was looking beautiful. Many people thought it was the best time for seeing the country. It was a fine autumn, but the local farmers thought the signs pointed to a hard winter. Thus she chatted, until the glass of sherry was finished. Then she lapsed into silence, with a certain expectancy in her mild glance, as though waiting for Colwyn to announce the object of his visit.

"I presume you have come down to see Phil?" she said, as Colwyn did not speak. "Unfortunately he is not at home," she went on, answering her own question in the feminine manner. "He has gone to Devon with Mr. Musard for a few days. It was my idea. I wanted him taken out of himself. He is moping terribly, and of course that is bad for him. I hope to persuade him to go with Vincent for a complete change when this—this terrible business is finished." Again her eye sought his.

"When do you expect them to return?"

"To-morrow night. Phil would not stay away longer. He has been expecting to hear from you. Can you stay till then?"

"Quite easily. In fact, I came down prepared to stop for a day or so. I have some further inquiries to make which will occupy me during that time."

"Then of course you will stay with us, Mr. Colwyn."

"You are very kind, but I do not wish to trouble you. I have engaged a room at the inn."

"It is no trouble. I will send down a man for your things. Phil would not like you to stay at the inn—neither should I." Miss Heredith rose as she spoke. "Please do whatever you wish, Mr. Colwyn. I quite understand that you have work to do, and wish to be alone."

"Thank you. Then I shall stay."

Colwyn sat for a while after she had left him, forming his plans. He was grateful to her for a tact which had not transgressed beyond the limits of unspoken thought during their brief interview, but he was more pleased with the fortuitous absence of Phil and Musard at that period of his investigations. He welcomed the opportunity of working unquestioned, because he was not prepared to disclose the statements of Nepcote and Hazel Rath to any of the inmates of the moat-house until he had tested the feasibility of both stories in the setting of the crime.

"It has all turned out very fortunately, so far," was the thought which arose in his mind. "And now—to work."

He glanced at his watch. It was nearly four o'clock. His immediate plans were a walk to Weydene, and another observation of the bedroom which Mrs. Heredith had occupied in the left wing. He decided to leave his investigation of the room until later so as to have the advantage of the waning daylight in his walk across the fields.

When he returned to the moat-house it was dark, and on the stroke of the dinner hour. That meal he took with Sir Philip and Miss Heredith in the faded state of the big dining-room—three decorous figures at a brightly lit oasis of snowy linen and silver, with the sober black of Tufnell in the background. Sir Philip greeted Colwyn with his tired smile of welcome. He seemed somewhat frailer, but quite animated as he pressed a special claret on his guest and told him, like a child telling of a promised treat, that he was dining out the following night. He insisted on giving the wonderful news in detail. He had yielded to the solicitations of an old friend—Lord Granger, the ambassador, who had just returned to Granger Park after five years' absence from England, and would take no denial. But it was Alethea's doing—she had arranged it all.

"I'm going to put back the clock of Time," he said, with a feeble chuckle. "Put the hands right back."

"I think it will do him good, don't you, Mr. Colwyn?" said Miss Heredith with a wistful smile.

"I have no doubt of it," said Colwyn with an answering smile. "A meeting with an old friend is always a good thing. Are you going with Sir Philip?"

"Oh, yes. I wouldn't go without her," said the baronet, with the helpless look of senility. "You're going, aren't you, Alethea?"

"Of course, Philip," was the gentle response.

This conversation, slight and desultory as it was, gave sufficient indication to the detective of the heavy burden Miss Heredith was bearing. The baronet could talk of nothing else during the remainder of the dinner, and when the meal was finished he begged his guest to excuse him as he wished to obtain a good night's rest to fortify him against the excitement of the coming outing. With an apologetic smile at Colwyn his sister followed him from the room.

The old butler busied himself at the sideboard as Colwyn remained seated at the table sipping his wine. His movements were so deliberate as to convey a suspicion that he was in no hurry to leave the room, and the glances he shot at Colwyn whenever he moved out of the range of his vision carried with them the additional suggestion that the detective was the unconscious cause of his slowness. More than once, after these backward glances, he opened his lips as though to speak, but did not do so. It was Colwyn who broke the silence.

"Tufnell!" he said.

"Yes, sir?" The butler deposited a dish on the sideboard and stepped quickly to the detective's chair.

"I want to ask you a question or two. It was you who found the back door of the left wing unlocked on the night of the murder, was it not?"

The butler gravely bowed, but did not speak.

"What made you try the door? Did you suspect that it was unlocked?"

"No; it was just chance that caused me to turn the handle. I'm so used to locking up the house at nights that I did it without thinking. I certainly never expected to find it unlocked, and the key in the inside of the door. That was quite a surprise to me. I have often wondered since who could have unlocked it and left the key in the door."

"You told me last time I was here that this door is usually locked and the key kept in the housekeeper's apartments. I suppose there is no doubt about that?"

"Not the least, sir. The key is hanging there now with a lot of others. Nobody ever thinks of using the door. That is why I was so astonished to find it open that night."

"If the key was hanging with a number of others it might have been taken some time before and not be missed?"

"That's just it, sir. It might not have been missed by now if I had not discovered it that night."

"What time was it when you found it?"

"Shortly before six o'clock—getting dusk, but not dark."

"You are quite sure you locked the door after finding it open?"

"There can be no doubt of that, sir. The lock was stiff to turn, and I tried the handle of the door to make sure that I had locked it properly."

"Did you return the key to the housekeeper's apartments immediately?"

"I intended to return it after dinner, but I forgot all about it in the excitement and confusion. It was still in my pocket when I informed Mr. Musard about it."

"Here is another question, Tufnell, and I want you to think well before answering it. Do you think it would have been possible for anybody to enter the house and gain the left wing unobserved while the household was at dinner that night?"

"I have asked myself that question several times since, sir—feeling a certain amount of responsibility. It would have been difficult, because the windows of the downstairs bedrooms of the left wing were all locked. There was always the chance of some of the servants seeing anybody crossing the hall on the way to the staircase, unless the—person watched and waited for an opportunity."

Colwyn nodded as though dismissing the subject, but the butler lingered. Perhaps it was his realization of the implication of his last words which gave him the courage to broach the matter which had been occupying his mind.

"Might I ask you a question, sir?" he hesitatingly commenced.

"What is it?"

"It's about the young woman who has been arrested, sir. Is there any likelihood that she will be proved innocent?"

"You must have some particular reason for asking me that question, Tufnell."

"Well, sir, I am aware that Mr. Philip thinks her innocent."

"So you told me when I was down here before, but that is not the reason for your question. You had better be frank."

"I wish to be frank, sir, but I am in a difficulty. I have learnt something which seems to have a bearing on this young woman's position, which I think you ought to know, but I have to consider my duty to the family. It was something—something I overheard."

"If it throws the slightest light on this crime it is your duty to reveal it," the detective responded gravely. "You are aware that I have been called into the case by Mr. Heredith because he is not convinced of Hazel Rath's guilt."

"Quite so, sir. For that reason I have been trying to make up my mind to confide in you. When you have heard what I have to say you will understand how hard it is. It relates to Mr. Philip, sir. Since his illness I have been worried about his health, because he is so changed that I feared he might go mad with grief. He hardly speaks a word to anybody, but sometimes I have seen him muttering to himself. The night before he went away with Mr. Musard he did not come down to dinner. Miss Heredith was going to send a servant to his room in case he had not heard the gong, but I offered to go myself. When I reached his bedroom, I heard the most awful sobbing possible to imagine. Then, through the partly open door, I heard Mr. Philip call on God Almighty to make somebody suffer as he had suffered. He mentioned a name—"

"Whose name?"

The butler looked fearfully towards the closed door, as though he suspected eavesdroppers, and then brought it out with an effort:

"Captain Nepcote, sir."

Colwyn had expected that name. Nepcote's statement on the previous night had led him to believe that Philip Heredith had suspected Nepcote's relations with his wife, but could not bring himself to disclose that when he sought assistance. It was Colwyn's experience that nothing was so rare as complete frankness from people who came to him for help. It was part of the ingrained reserve of the English mind, the sensitive dread of gossip or scandal, to keep something back at such moments. The average person was so swaddled by limitations of intelligence as to be incapable of understanding that suppressed facts were bound to come to light sooner or later if they affected the matter of the partial confidence. Of course, there was sometimes the alternative of a reticence which was intended to mislead. If that entered into the present case it was an additional complication.

"What interpretation did you place on these overheard words?" he asked the butler. "Did you suppose that they referred to the murder?"

"Well, sir—" the butler hesitated, as if at a loss to express himself. "It was not for me to draw conclusions, sir, but I could not help thinking over what I had heard. I know Mr. Philip believed the young woman to be innocent, and—Mrs. Heredith was shot with Captain Nepcote's revolver."

"I see. You had no other thought in your mind?"

"No, sir. What else could I think?"

The butler's meek tones conveyed such an inflection of surprise that Colwyn was convinced that he, at all events, had no suspicion of the secret between Mrs. Heredith and Nepcote.

"Your confidence is quite safe with me, Tufnell," the detective added after a pause. "But I cannot answer your question at present."

"Very well, sir." The butler turned to the sideboard again without further remark, and left the dining-room a few minutes later.

Colwyn went to his room shortly afterwards, and occupied himself for a couple of hours in going through his notes of the case. It was his intention to defer his visit to the bedroom in the left wing until the household had retired, so as to be free from the curious speculations and tittle-tattle of the servants.

The moat-house kept country hours, and when he had finished his writing and descended from his room he found the ground floor in darkness. A clock somewhere in the stillness chimed solemnly as he walked swiftly across the hall. Its strokes finished proclaiming the hour of eleven as he mounted the staircase of the left wing.

The loneliness of the deserted wing was like a moving shuddering thing in the desolation of the silence and the darkness. It was as though the echoing corridor and the empty rooms were whispering, with the appeal of the forgotten, for friendly human companionship and light to disperse the horror of sinister shapes and brooding shadows which lurked in the abode of murder. Colwyn entered the bedroom where Mrs. Heredith had been murdered, and by the ray of his electric torch crossed to the bedside and switched on the light.

He stood there motionless for a while, trying to picture the manner and the method of the murder. If Hazel Rath had spoken the truth, the murderer had stood where he was now standing when the girl entered the room in the darkness. Had the light from the corridor, streaming through the open door, revealed her approaching figure to him? How long had he been there in the darkness, waiting for the moment to kill the woman on the bed?

If Nepcote was the murderer he must have entered almost immediately before, because he could not have reached the moat-house until nearly half-past seven, and the shot was fired at twenty minutes to eight. How had he known that Mrs. Heredith was there alone, in the darkness? A secret assignation might have been the explanation if the time had been after, instead of before the household's departure for the evening. But even the most wanton pair of lovers would hesitate to indulge their passion while the risk of chance discovery and exposure was so great.

As he pondered over the two stories Colwyn did not attempt to shut his eyes to the fact that Hazel, on her own showing, fitted into the crime more completely than Nepcote. She had ample opportunities to slip into the room and murder the woman who had supplanted her. She had really strengthened the case against herself by the damaging admission that she had sought Mrs. Heredith's room in secret just before the crime was committed. Her explanation of the scream and the shot was so improbable as to sound incredible. It was not to be wondered that Scotland Yard preferred to believe that it was the apparition of the frantic girl, revolver in hand, which had caused her affrighted victim to utter one wild scream before the shot was fired which ended her life.

But Colwyn had never allowed himself to be swayed too much by circumstance. Appearances were not always a safe guide in the complicated tangle of human affairs. Things were forever happening which left experience wide-eyed with astonishment. The contradictions of human nature persisted in all human acts. In this moat-house mystery, the grimmest paradox of his brilliant career, Colwyn was determined not to accept the presumption of the facts until he had satisfied himself that no other interpretation was possible. His subtle mind had been challenged by a finger-post of doubt in the written evidence; a finger-post so faint as to be passed unnoticed by other eyes, but sufficiently warning to his clearer vision to cause him to pause midway in the broad track of circumstantial evidence and look around him for a concealed path.

It was the point he had mentioned to Caldew at his chambers after reading the copy of the coroner's depositions which Merrington had lent him. While perusing them he had been struck by a curious fact. The medical evidence stated that the cause of death was a small punctured wound not larger than a threepenny piece, but added the information that the hole in the gown of the dead woman was much larger, about the diameter of a half-crown. The Government pathologist had formed the opinion that the revolver must have been held very close to the body to account for the larger scorched hole. That inference was obvious, but Colwyn saw more in the two holes than that. It seemed to him that the live ring of flame caused by the close-range shot must have been extinguished by the murderer, or it would have continued to smoulder and expand in an ever-widening circle. And that thought led to another of much greater significance. The shot had been fired at close range to ensure accuracy of aim or deaden the sound of the report. But, whichever the murderer's intention, the second purpose had been achieved, intentionally or unintentionally. How had it happened, then, that the sound of the report had penetrated so loudly downstairs?

As Colwyn moved about the room, examining everything with his quick appraising eye, he noticed that the position of the bed had been changed since he last saw it. The head was a trifle askew, and nearer to the side of the wall than the foot. The difference was slight, but Colwyn could see a portion of the fireplace which had not been visible before. The bed stood almost in the centre of the room, the foot in line with the door, and the head about three or four feet from the chimney-piece. In noting this rather unusual position during his last visit, Colwyn had formed the conclusion that it had been chosen for the benefit of fresh air and light during the summer months, as the window, which looked over the terraced gardens, was nearer that end of the room.

Colwyn approached the head of the bed and bent down to examine the bedposts. A slight groove in the deep pile carpet showed clearly enough that the bed had been pushed back a few inches. The change in position was so trifling that it might have been attributed to the act of a servant in sweeping the room if a closer examination had not revealed the continuance of the groove under the bed. The inference was unmistakable: the bed, in the first instance, had been pushed much farther back on its castors, and then almost, but not quite, restored to its original position.

Had the bed been moved to gain access to the fireplace? He could see no reason for such a proceeding. It was too early in the autumn to need fires, and the room had not been occupied since the murder. In any case, the appearance of the grate showed that no fire had been lit. There was ample space to pass between the head of the bed and the fireplace, though perhaps not much room for movement. On his last visit Colwyn had looked into this space to test its possibilities of concealment. In the quickened interest of his new discovery he pushed the bed out of the way and examined it again.

The first thing that caught his eye was a scratch on the polished surface of the register grate. It looked to be of recent origin, and for that reason suggested to Colwyn's mind that the bed had been moved by somebody who wanted more room in front of the grate. For what purpose? He turned his attention to the grate itself in the hope of obtaining an answer to that question.

The grate was empty, and in the housewifely way a sheet of white paper had been laid on the bottom bars to catch occasional flakes of soot from the chimney. But there were no burnt papers or charred fragments to suggest that the grate had recently been used. Dissatisfied and perplexed, Colwyn was about to rise to his feet when it chanced that his eyes, glancing into a corner, lighted on something tiny and metallic in the crevice between the white paper and the side bars of the grate. Wondering what it was, he succeeded in getting it out with his finger and thumb. It was a percussion cap.

This discovery, strange as it was, seemed at first sight far enough removed from the circumstances of the murder, except so far as it brought the thought of lethal weapons to the imagination. But a weapon which required a percussion cap for its discharge had nothing to do with Violet Heredith's death. She had been killed by a bullet which fitted Nepcote's revolver, which was a pinfire weapon. The medical evidence had established that fact beyond the shadow of a doubt. Moreover, the percussion cap was unexploded, which seemed to make its presence in the grate even more difficult of explanation. It looked as though it had been dropped accidentally, but how came it to be there at all? The strangeness of the discovery was intensified by the knowledge that percussion caps and muzzle-loading weapons had become antiquated with the advent of the breech-loader. Who used such things nowadays?

By the prompting of that mysterious association of ideas which is called memory, Colwyn was reminded of his earlier visit to the gun-room downstairs, and Musard's statement about the famous pair of pistols in the brass-bound mahogany box, which "carried as true as a rifle up to fifty yards, but had a heavy recoil." They belonged to the period between breech-loaders and the ancient flint-locks, and were probably muzzle-loaders. With that sudden recollection, Colwyn also recalled that Musard had been unable to show him the pistols because the key of the case had been mislaid or lost.

This incident, insignificant as it had appeared at the time, seemed hardly to gain in importance when considered in conjunction with the discovery of the cap in the grate. Apart from the stimulus to memory the percussion cap had produced, there was no visible co-ordination between the two facts, because it was, apparently, quite certain that Mrs. Heredith had been shot by Nepcote's revolver, and by no other weapon. But the balance of probabilities in crime are sometimes turned by apparently irrelevant trifles which assume importance on investigation. Was it possible that the key of the pistol-case had been deliberately concealed because the box had something to hide which formed a connection between the pistols and the presence of the cap in the grate? That inference could only be tested by an examination of the case of pistols. The experiment was undoubtedly worth trying. Colwyn left the room and descended the stairs.