The girl who entered the room a moment later was tall and graceful, with a yearning expression in her soft dark eyes, as though in search of a happiness which had been denied her by Fate. Her appearance was one of unusual refinement. She had not a trace of the coarsened blowzy look so common in English country girls; there was nothing of rustic lumpishness in her slim figure, and there was more than mere prettiness in her exquisite small features, her thick dark hair, her clear white skin with a tracery of blue veins in the temples. Her high-bridged nose and firm chin suggested some force of character, but that suggestion was counteracted by her wistful tender mouth, with drooping underlip. The face, on the whole, was a paradoxical one, containing elements of strength and weakness, and the eyes were the index to a strange passionate nature.

She advanced into the room quietly, with a swift glance, immediately veiled by drooped lids, at the faces of the police officials who were awaiting her. When she reached the far end of the table at which they were seated she stopped and stood with her hands clasped loosely in front of her, as though waiting to be questioned.

"Please sit down, Miss Rath," said Captain Stanhill politely. "We wish to ask you a few questions."

The girl seated herself in a chair some distance away from her mother, and this time she surveyed the men before her with an air of indifference which was obviously simulated.

But again she quickly dropped her eyes, for Merrington was staring at her with a look of amazement, as though confronted with a familiar presence whose identity he could not recall. He glanced from Hazel to her mother, and his eyes fastened themselves fiercely on the housekeeper with the satisfaction of a man who had solved an elusive puzzle.

"So we have met before, Mrs. Rath," he said. "You are—"

"No, no! Please keep silent in front of my daughter," broke in the housekeeper hurriedly.

"I was not mistaken. I remembered this woman's face this morning, but I could not then recall where I had seen her before," pursued Merrington, turning to Captain Stanhill and speaking with a sort of reflective cruelty. "Her daughter's face supplies the clue. She is the image of her mother as I remember her when she stood her trial at Old Bailey fifteen years ago. She was tried for—"

"I beg of you not to say it!" Mrs. Rath started from her seat, and looked wildly around as though seeking some avenue of escape from a threatened disaster.

"Is it necessary to go into this, Merrington?" asked Captain Stanhill in his mild tones, glancing from the excited woman to his colleague with the troubled consciousness that he was assisting in a scene which was distasteful to him.

"Of course it is necessary if we want to get at the truth of this case," retorted Merrington. "You needn't be concerned on Mrs. Rath's account," he went on, with a kind of savage, disdainful irony. "A woman who has been tried as an accessory to murder is not likely to be squeamish. Her name is not Rath. It is Theberton—Mary Theberton. She and her husband were tried at Old Bailey fifteen years ago for the murder of a man named Bridges. The trial made a great stir at the time. It was known as 'The Death Signal Case'."

Caldew looked at the housekeeper with a new interest. He readily recalled the notorious case mentioned by Merrington. Theberton was an Essex miller, who, having discovered that his young wife was in the habit of signalling his absence to Bridges by means of a candle placed in her window, had compelled her to entice him to the cottage by the signal, and was then supposed to have murdered him by throwing him into the mill dam. But though Bridges was seen entering the cottage and was not seen afterwards, the charge of murder failed because the detectives were unable to find his body. Theberton protested his innocence; Mary Theberton said her husband locked her in her room before admitting Bridges, and she knew nothing of what took place between the two men.

There was much popular sympathy with her during the trial as the belief gained ground that the relations between her and Bridges were innocent, though indiscreet; the outcome of a craving for sympathy which had led an unhappy young wife to confide her troubles to a former schoolfellow. She was the daughter of an architect, and had been reared in refinement and educated well, but she had been disowned by her father for marrying beneath her. Her husband ill-used her, and her story was that she had sought the assistance of an old schoolfellow in order to go to London to earn a living for herself and her little daughter. When the trial was over Theberton emigrated, and his wife disappeared, although there was some talk of putting on foot a public subscription for her. This was the end of "The Death Signal Case," for the mystery of the disappearance of Bridges was never solved.

Caldew wondered by what strange turn of Fortune's wheel the woman before him had come to be housekeeper at the moat-house. It was certain that Miss Heredith knew nothing of the black page in her past, because Miss Heredith, in spite of her kind heart and rigid church principles, was the last person to appoint anybody with a tainted name to a position of trust in her household. She was too proud of the family name to do such a thing. The fact that the housekeeper had held the post so long without discovery was proof of the ease with which identity could be safely concealed from everything except chance. Although her nervous demeanour suggested that she had been walking on a razor edge of perpetual suspense in her quiet haven, ever dreading detection, it seemed to Caldew that she might have gone undiscovered to her grave but for a trick of Fate in selecting Superintendent Merrington to investigate the moat-house murder. Fate, after its cruel fashion, had left her on her razor edge for quite a long while before toppling her over, and Caldew reflected that he had been made the instrument of her fall.

But what lay beyond the exposure of the housekeeper's identity? Why had she deceived Merrington about her daughter's presence in the house? Was it only the fear that Merrington would recognize her in her early likeness to her daughter, or were her falsehoods intended to deceive the detectives about Hazel's movements at the time of the murder? What would the girl say? The situation was full of strange possibilities.

While these reflections were passing through Caldew's head there was silence in the room, broken only by the clock on the mantelpiece ticking loudly, with pert indifference to human affairs. Merrington, after dragging the hidden and forgotten tragedy to light, remained quiet, watchfully noting the effect on mother and daughter. The mother stood without a word or gesture, her hand stiffened in arrested protest, like a woman frozen into silence. The girl's look was directed towards her mother with the fixity of gaze of a sleeper awakened in the horror of a bad dream. At least in their stillness they were both in accord. Then Hazel glanced wonderingly at the faces of the others in the room, with the fatigued indifference of a returning consciousness seeking to regain its bearings. This phase passed, and in the sudden wild burst of tears which followed was the belated realization of the meaning of her mother's exposure; the shame, the agony, the disgrace which it implied. With a quick movement she rose from her seat, walked across to her mother, and caught hold of her hand.

"Mother!" she said.

But her mother turned away from her, and, sinking in her chair, covered her face in her hands with a shamed gesture, like a woman cast forth naked in the light of day.

"Never mind your mother just now," said Merrington, as the girl bent over as though to sooth her. "Please return to your seat and answer my questions."

Hazel turned round at the sound of his voice, but stood where she was, regarding him anxiously.

"You stayed here last night with your mother, I understand?" Merrington continued.

"Yes."

"When did you arrive here?"

"Yesterday afternoon."

"Where from?"

"From Stading, by train. I had an afternoon off, and I came to see my mother."

"How long is it since you visited her previously?"

"It must be about three months," said Hazel, after a short reflection.

"Do you always allow three months to elapse between your visits?"

"No." There was a trace of hesitation in the response.

"You used to come oftener?"

"Yes."

"How often?"

"Nearly every week." This time the hesitation before the reply was plainly apparent.

"Why did you allow so long a time to elapse between this visit and the last one when you had previously been in the habit of seeing your mother nearly every week?"

Hazel again hesitated, as though at a loss for a reply.

"I have been so busy," she murmured at length.

"Is this your first visit to the moat-house since Mrs. Heredith came here to live?"

"Yes." The response was so low as to be almost inaudible.

Caldew, who was the only person in the room with the deeper knowledge to divine the drift of these questions, realized with something of a shock that Merrington, with fewer facts to guide him, had reached his absolute conclusion about the events of the last half-hour while he had wandered perplexedly in a cloud of suspicions. The mental jump had been too great for him, but Merrington had not hesitated to take it. Caldew waited eagerly for the next question. It was some time in coming, and when it did come it was not what Caldew expected. As though satisfied with the previous answers he had received, Merrington branched off on another track.

"How did you spend last night?" he asked abruptly.

"I do not understand you." There was the shadow of fear in the girl's dark eyes as she answered.

"I will put it more plainly then. How did you occupy the time between your arrival at the moat-house and bedtime?"

"I spent it with my mother in her rooms."

"Were you there all the time?"

It seemed to Caldew that the elder woman's attitude was that of a listener. Though she still kept her face buried in her hands, her frame slightly moved, as though she were listening to catch the reply.

"Yes." The word was spoken hurriedly, almost defiantly, but the girl's eyes wavered and fell under Merrington's direct glance.

"May I take it, then, that you were in your mother's room at the time Mrs. Heredith was murdered?"

This time Hazel did not reply audibly, but a faint movement of her head indicated an affirmative.

"What would you say if your mother admits that you left her room before the murder was committed, and that she did not see you until afterwards?"

It was a clever trap, Caldew reluctantly conceded, this idea of playing off the mother and daughter against each other, but one that he would have hesitated to use. The effect was instantaneous. Before the girl could frame her frightened lips in reply, her mother lifted her head sharply.

"I didn't say so! Don't answer him, Hazel, don't tell him. Oh!" Too late the wretched woman realized that she had betrayed her daughter, and she sank into a stupefied silence.

"Your mother has let the cat out of the bag," said Merrington to the girl, in a bantering tone. "Come, now," he added, changing swiftly into his most truculent mood. "We may as well have the truth, first as last. You were seen last night going up the hall in the direction of the left wing just before the murder was committed. Do you admit it?"

"I do." The admission was made in a low but calm tone.

"Then your last answer was untrue. What were you doing in the hall at that time?"

Hazel, staring straight in front of her, did not reply, but her quickly moving breast betrayed her agitation.

"Did you hear me? I asked what were you doing in the hall last night."

"I shall not tell you."

"Did you go upstairs?"

"I shall not tell you."

These replies were given with a firm readiness which was in striking contrast to her previous hesitation. She was like a person who had been forced on to a dangerous path she feared to tread, and had summoned fortitude to walk it bravely to the end.

"Of course you realize the position in which you place yourself by your silence?" The quiet gravity with which Merrington put this question was, similarly, in the strangest contrast to his former hectoring style. "It is my duty to warn you that you are placing yourself in a grave situation. Once more, will you answer my questions?"

"I will not." The answer was accompanied by a gesture which contained something of the carelessness of despair.

"Then you must abide the consequences." He turned to Captain Stanhill and Caldew. "It will be necessary to search the housekeeper's rooms. Lumbe, you remain here and take charge of these two women. Do not allow either of them to leave the room on any pretext. You had better keep the door locked until we return."

He strode out of the room followed by Captain Stanhill and Caldew, to the manifest trepidation of two maidservants outside, who had plainly no business there. It was apparent that Milly Saker had been talking, and that strange rumours were agitating the moat-house underworld.

"Where are the housekeeper's rooms?" said Merrington, abruptly accosting one of the fluttered girls. "Come now, don't stand gaping at me like a fool, but take us there directly."

The terrified girl went quickly ahead along a corridor leading from the main hall. Turning down a narrower passage near the end she paused outside a closed door and said:

"This is the housekeeper's room, sir."

"Stop a minute," said Merrington. "Does the housekeeper occupy only one room?"

"No, sir, there are two. A sitting-room, with a bedroom opening off it."

"She has no other room in any other part of the house?"

"Oh, no, sir."

"That will do. You may go."

The maid needed no second bidding, but scuttled back towards the corridor like a scared hen making for cover. Merrington flung open the door in front of him and entered.

The room was well and simply furnished in the style of the house, but the personal belongings and the bindings of some books suggested a mind not out of harmony with the refinement of its surroundings. Merrington, with a swift and comprehensive glance around him, began to upset the neat arrangement and feminine order of the apartment with a thorough and systematic search.

Caldew watched him for a moment, and then walked across to the door of the inner room and entered it. The bedroom was large and airy, and the appointments struck the note of dainty simplicity. Caldew was quick to notice a girl's hat, with a veil attached, cast carelessly on the toilet-table.

He made a circuit round the bed and approached the table to look at the hat. A tight knot and a slight tear in the gossamer indicated that it had been discarded very hastily, and Caldew wondered whether Hazel had it on, waiting for an opportunity to slip away from the moat-house, when he had knocked at the door to summon her to the library.

As he put the hat down his eye fell on a pincushion by the mirror, and he gave a start of surprise. In the midst of hatpins at various angles he saw the little brooch which had disappeared from the death-chamber. The stone with the greenish reflection shone clearly against the blue and gold shot-silk of the pincushion; the portion of the clasp which was visible revealed the beginning of the scratched inscription of "Semper Fidelis." The absence of any attempt to conceal the brooch was proof that its owner was under the delusion that nobody had seen it lying in the death-chamber. Caldew felt a thrill of professional vanity at the success of his ruse.

His own name uttered in a peremptory shout from the next room caused him to pick up the brooch and hasten thither. The first sight that met his eye was the flushed triumphant face of Merrington bending over some articles on the table. Caldew's view of the objects was obscured by Captain Stanhill, who was also examining them, but he guessed by the attitude of both men that a valuable find had been made. He advanced eagerly to the table and saw, lying between them, a small revolver and a handkerchief. The white cambric of the handkerchief was stained crimson with blood.

The room was in great disorder. Superintendent Merrington, in the impetuosity of his search, had reduced the previous order to chaos in the course of a few minutes. Drawers had been opened and their contents strewn about the floor, rugs and cushions had been flung into a corner of the room, and the doors of a cabinet had been forced. Even the pictures on the wall had been disarranged, and some of the chairs were knocked over.

"Where did you find these things?" asked Caldew, picking up the revolver and examining it.

"In that gimcrack thing over there." Merrington pointed to a slight, elegant writing-table standing in a corner of the room. "Isn't it a typical female hiding-place? About as safe as burying your head in the sand. The drawer had been locked and the key taken away, but it was quite easy to open. The lock is a trumpery kind of thing, with the bolt shooting into the soft wood."

"I see that the revolver is still loaded in five chambers," said Caldew, as he put down the weapon.

"Yes, and the sixth has been recently discharged. We don't require much clearer evidence than that. And look at this handkerchief. The blood on it is hardly dry yet."

Caldew took the handkerchief in his hand. As Merrington remarked, the blood on it was hardly dry. It was a small linen square, destitute of feminine adornment except for a dainty "H R" worked in silk in one corner. The letters were barely visible in the blood with which the whole handkerchief was saturated.

"I wonder how she got the blood on the handkerchief?" said Caldew. "Did she try to stop the bleeding after shooting Mrs. Heredith?"

"It would be just like a woman to do so," grunted Merrington. "Women are fond of crying over spilt milk—especially when they have spilt it themselves. However, that's neither here nor there. The point is that this is the girl's handkerchief, and this is the revolver with which she shot Mrs. Heredith."

"But what was her motive for committing such an atrocious crime?" asked Captain Stanhill in bewilderment.

"Jealousy," responded Merrington promptly. "I saw the possibility of that motive as soon as I heard Milly Saker's story, and learnt that Hazel Rath had lived for some years in the moat-house. Young Heredith and she must have been thrown together a lot before the war, and there was doubtless a flirtation between them which probably developed into an intrigue. There are all the materials at hand for it—a well-born idle young man, a girl educated above her station, a lonely country-house, and plenty of opportunity. I know the type of girl well. These half-educated protÉgÉes of great ladies grow up with all the whims and caprices of fine females, and their silly little heads are easily turned. Probably this girl imagined that young Heredith was so captivated by her pretty face that he would marry her. When she learnt that she had been dropped for somebody else she brooded in secret until her unbalanced nature led her to commit this terrible crime. Moreover, she is the daughter of a woman with a queer past, who has been living under an assumed name for the past fifteen years."

"Do you think mother and daughter have acted in collusion in this murder?" Caldew asked.

"That is a question I would not care to answer offhand," responded Merrington thoughtfully. "Undoubtedly the mother shielded the daughter and lied to save her, and she obviously knew that the girl was absent from her room at the time the murder was committed. How far this implies guilty knowledge, or the acts of an accomplice, we are not yet in a position to say. We will arrest the daughter, and detain the mother—for the present, at all events. Whether we charge the mother as well as the daughter will depend on our subsequent investigations. It will be no novelty for the mother to be charged as accessory in a murder case," concluded Merrington, with a grim smile.

"We have no direct evidence that the girl went upstairs last night," said Caldew, with a reflective air. "Milly Saker did not see her going upstairs, and apparently nobody saw her coming away."

"No direct evidence, it is true. But the presumptive evidence is so strong that it is hardly needed. In the first place, Milly Saker saw her going down the hall in the direction of the left wing just before the murder was committed. Next day—this morning—the housekeeper sent Milly Saker out of the way before she could be questioned by the police. That act suggests two inferences. First, Mrs. Rath, as she calls herself, had some inkling that Milly Saker saw her daughter in the hall on the previous night, and secondly, that Mrs. Rath feared, in the light of subsequent events, to let it be known that her daughter was seen walking down the hall before the murder was committed. From these inferences we may conclude that, even if the mother had no actual knowledge of the crime, she believed that her daughter was guilty. Her subsequent actions to-day confirm that theory in every respect. And, of course, the recovery of this revolver and the girl's handkerchief in her mother's rooms, where she slept last night, is the strongest possible proof that the girl shot Mrs. Heredith."

"Of course there can be no doubt of that. It would be impossible to find a stronger case of circumstantial evidence," said Caldew earnestly. "But here is a piece of direct evidence. Look here!" He produced the little brooch from his pocket and placed it on the table beside the revolver and the handkerchief. "This is the brooch I told you about. It is the brooch I saw in Mrs. Heredith's room which disappeared while I was downstairs. I found it stuck in a pincushion in the next room, beside the girl's hat. She must have realized that she dropped it in the murdered woman's bedroom, and seized the opportunity to return for it while I was out of the room. That is a piece of direct evidence that she was in Mrs. Heredith's bedroom."

"So you were right about the brooch. I owe you an apology for that, Caldew," said Merrington. He placed the little trinket in his big hand, and turned it over with his finger. The inscription on the back caught his eye, and he held it closer to read it. "Semper Fidelis!" he exclaimed. "The words are typical of the girl. The wishy-washy sentiment would appeal to her, and she's of that partly educated type which thinks a Latin tag imposing. I wonder who gave it to her? Oh, I have it! It was probably a gift from young Heredith, and she added the inscription on her own account so as to enhance the value of the gift and keep her 'Faithful Always.'"

Once more Caldew reluctantly admitted to himself that Merrington's deductions were more swift and vigorous than his own, but he was secretly annoyed to think that the other had gained partly by guesswork the solution of a clue which had caused him so much thought and perplexity.

"The brooch is no more direct evidence than the revolver and handkerchief," continued Merrington. "The girl, unless she is a born fool, is not likely to admit ownership of any one of them. She would be putting the rope round her own neck to do so."

"I realize that," replied Caldew. "But I think that she might be trapped into giving away that she owns the brooch. Women are very impulsive where the loss of ornaments is concerned, and then their actions are instinctive. I have frequently noticed it."

"And how do you propose to find out?" asked Merrington.

"By asking her."

"You'll get nothing out of this girl for the asking," replied Merrington. "She runs deeper than that, or I am very much mistaken. However, ask your own questions, by all means, after I have questioned her about the revolver and the handkerchief. Let us get back to the library."

They returned to the library. Sergeant Lumbe opened the door in response to their knock, his face furrowed with the responsibilities of office. Mother and daughter were sitting where they had left them, but the elder woman had regained some measure of composure, and was staring drearily in front of her. She did not look at the police officials as they entered, but Hazel glanced towards them, and her eyes fell on the revolver and handkerchief which Merrington carried in his hand. It seemed to Caldew that her face remained unmoved. Merrington walked over to her.

"You must consider yourself under arrest on a charge of murdering Mrs. Heredith," he said, in quiet, almost conversational tones. "This revolver and this handkerchief were found in your mother's sitting-room. If you have any explanation to make you may do so, but it is my duty to warn you that any statement you make now may be used in evidence against you later on."

"I have nothing to say," replied the girl simply.

"You decline to say how this revolver came into your possession, or make any explanation about the bloodstains on this handkerchief?"

"Yes."

"Do you also refuse to tell us what you have done with the brooch you were wearing last night?" added Caldew.

The girl, with an impulsive instinctive gesture, hastily put her hand to the neck of her blouse, then, realizing that she had unconsciously betrayed herself, she let it fall slowly to her side.