it was not from tracey that laura learned the details of the ajax villa tragedy. leaving gerty in the garden with her lover, miss mason walked round to the house, eager to hear all that had taken place. a rumour about the murder had crept round troy, and a few curious people were staring at the windows. but no policeman was to be seen. the inspector kept his officers on guard inside the villa, thinking, and very rightly, that the sight of a constable in the garden would provoke inquiry, and bring onlookers. derrick wished the matter kept as quiet as possible until the arrival of mr. fane. the body of the unfortunate woman had been removed to one of the bedrooms, and a policeman watched at the door. everything in the house was in the same order as it had been when entered by mulligan, and derrick himself took up his quarters in the white room. here he issued orders.

"if a young lady calls to see me, let her in," he said; "but no one else is to be admitted."

"mr. tracey, sir?" asked mulligan, who was full of official pride.

"yes; certainly. i except him. but no one else, mind."

"what about the wire to mr. fane, sir?"

"i'll send it as soon as i get his address from the lady. ah"--he nodded as a ring came to the door--"there she is."

laura entered the room, looking pale and discomposed, evidences of emotion of which derrick took note. to be sure, it was natural that a girl of this tender age should be unstrung by the tragedy which had taken place, and derrick scarcely expected to see her other than moved. but having regard to the crime, he was suspicious of all the fane family. he admired laura's fresh beauty, and placed a chair for her, apologising meanwhile for the disagreeable duty he had to perform.

"but i am sure you will excuse me, miss mason," said the gallant derrick. "i will ask as few questions as possible."

"i really don't know what questions you can ask me," said laura.

"oh, that is an easy matter, miss mason. however, we had better clear the ground, so that we may understand one another. it was mr. tracey who told me that you are the sister-in-law of mr. fane, and i requested him to bring you round. is he below?"

"no; i preferred to come myself. mr. tracey is of a very inquiring nature, and i don't want him to hear all i may have to tell you."

derrick shook his head. "i fear you will be obliged to let the whole of london hear, miss mason. there will be an inquest."

"must i appear at that?"

"certainly. you may be able to identify the woman."

"i fear not, from the description mr. tracey gave of her."

derrick looked at her sharply as she said this. her eyes met his fairly, and she did not flinch from his scrutiny. but her bosom rose and fell hurriedly, her cheeks flushed, she passed her tongue over her dry lips. all these things gave evidence of inward discomposure. whether she knew anything, derrick was not prepared to say. but if she did, he was sure it would be difficult to make her speak out. laura was innocent and young, but in spite of her delicate appearance, she had a strong will. derrick guessed as much from the way in which she tightened her lips. but he could not conceive that she could hold out against his examination. "have you anything to conceal?" he asked abruptly and rashly.

laura coloured still more and glanced at him indignantly. "how can you speak to me like that?" she said; "do you suspect me?"

"no. certainly not. but the affair is strange, miss mason."

"from the little i gathered from mr. tracey, it is," she assented.

"here is a house shut up," said derrick, pursuing his own train of thought; "left without even a caretaker----"

"there was no need for one to be left," interposed the girl. "my sister, mrs. fane, thinks that troy is a safe suburb. there have been no burglaries hereabouts, so she merely asked the police to keep an eye on the house. besides, she is away only for three weeks."

"when do mrs. fane and family return?"

"in six days."

"you remained behind?"

laura bowed. "my sister and i are not on very good terms," she began, "and i thought it best to remain with my friend, miss baldwin, while the house was shut up. but you were saying something."

"merely that it is queer this woman--this stranger--if she is a stranger, should obtain admittance into the house while those who own it are away. she came on saturday evening--at what time we are not as yet able to learn. no one saw her come. we do not know if she came alone or in the company of any one. but come she did, and entered the house. how did she get in?"

"i am as puzzled as you are, sir. but if you will let me see the body, i may be able to tell you if it is that of a stranger to me."

"we can do that later," said derrick. "meanwhile i wish to put a few questions. and even if this woman were not a stranger is it likely that she could enter the house?"

"no. so far as i know, my brother-in-law alone has a latch-key."

"is there not another possessed by a young man?"

laura looked out of the window while answering this question. "not that i know of," she said faintly.

derrick appeared satisfied with this reply, and took out his note-book. "answer my questions, please," he began. "who is mr. fane?"

"my brother-in-law. he is the second partner in the shipping firm of mason, son, and mason."

"oh! and why does not his name appear?"

laura explained. "the firm is an old one," she said; "there are two partners, my brother and walter fane. when my father died, the firm was mason, son, and mason, and as it is an old-established one, my brother did not change the name when mr. fane became a partner."

"when did mr. fane become a partner?"

"three years ago, when he married my sister julia!"

"did mr. fane bring any money into the business?" asked derrick; then seeing laura's look of surprise, he continued apologetically, "excuse me, miss mason, but i must know everything."

"i believe mr. fane brought very little money into the business. it was my sister julia who had the money, and she paid sufficient to my brother to buy walter a share. but i have no right to tell you these things," said laura, flushing. "if you wish to know anything further you must ask mr. fane himself."

"i intend to. will you give me his address?"

"ocean view, wandle road, westcliff-on-sea."

derrick noted this in his book. "i'll send a wire to him," he said, "as the inquest takes place to-morrow and we must have him present. by the way, do you know a young man with a pointed beard and slim figure? is he a visitor at this house?"

"not that i know of," said miss mason promptly. "i know no one of that type--with a pointed beard, i mean."

"yet such a young man came out of the house, and held the policeman in talk while his accomplice murdered this woman."

"were there two men, then?"

"we think so," answered derrick cautiously. "i presume, miss mason," he added, "you have been to this house since mrs. fane left it?"

"certainly not."

"but living so near--meadow lane is but a stone-throw away."

"quite so. all the same i had no reason to return here."

"you live in this house?"

"with my sister. yes."

"then your things are here?"

laura looked hard at derrick, trying to fathom his meaning. "i took all needful things with me, as though i were going on a long journey, mr. inspector. for nearly two weeks i have lived with mrs. baldwin, and have not been in achilles avenue."

"have you not passed the house?"

"i said that i had not been in achilles avenue," replied laura.

"then you know nothing," said derrick, obviously disappointed with the result of his examination.

"absolutely nothing."

the inspector nursed his chin, and thought with his eyes on the ground. there was nothing else he could ask. mr. fane was the owner of ajax villa, and as this unknown woman had been murdered therein, mr. fane alone would be able to say how she had come by her death. in his past life might be found the reason that the poor creature should be so slain. "what did mr. fane do before he joined the firm?"

"nothing," replied laura, rousing herself from her own thoughts; "he is possessed of independent means and travelled a great deal. i suppose he grew weary of so aimless a life. however, my sister persuaded him to become a partner, which he did, after he married her."

"hum!" said derrick, not finding this reply threw any light on the subject. then he cast his eyes round the room. "this is a queer place, miss mason. mrs. fane's idea?"

"no. mr. fane furnished the house. my sister does not like this room. it is too cold in its looks for her. mr. fane is fond of it. but the whole house was furnished before mr. fane married."

"for the marriage, i presume."

"no. mr. fane lived here as a bachelor for six months before he married my sister."

"but no doubt the engagement lasted six months, and mr. fane furnished the house as he thought your sister would like it."

"he did not. mr. fane married my sister at the end of three months, and before that he furnished the house according to his own taste."

derrick thought this strange. however, he did not ask any more questions, as he felt that he had rather exceeded the limits of an even official courtesy. "i am much obliged to you for replying so frankly to my questions, miss mason," he said. "if i have been too curious, the strange nature of this case must be my excuse. we will now inspect the body."

laura's cheeks grew even paler than they were. but she made no objection. silently she followed the inspector, moving indifferently through the house. only when they arrived at the door of the death-chamber did she draw back. "you have put the body into my room," she said resentfully.

"i am sorry," said derrick, opening the door, "but of course i was quite in ignorance."

"i shall never be able to sleep in the room again," murmured laura, and passed through the door which derrick held open.

out of delicacy the inspector did not enter with her. he remained outside, thinking over what she had said. it seemed to him that mr. fane had married very suddenly, and had taken his bride to a house which had not been furnished for her. the house was too large for a bachelor, and must have been intended for two. what if fane had been engaged to some one else, for whom the house was furnished, but the engagement being broken, and married miss julia mason so hurriedly. if this were so, the house with its strange white room which was not to the present mrs. fane's taste must have been furnished for the unknown woman. and perhaps the unknown woman was the poor soul who lay dead within. only fane had the latch-key, only fane could have admitted her, and then--here derrick broke off. he felt that he was taking too much for granted; that he was building up a theory on unsubstantial foundations. until he saw fane, and learned what kind of a man he was, it was impossible to formulate any theory. still, for his own satisfaction, derrick determined to ask laura a few more questions. it was at this moment she emerged, pale but composed.

"i do not know the woman at all," she said, before he could speak.

"you are quite sure?"

"perfectly. i never set eyes on her before. a pretty woman," added laura sadly, "and with quite a girlish face. i wonder what brought her here to meet her death."

"i wonder," said derrick; "and who could have killed her?"

"that is the mystery," sighed laura, turning to go away.

"it will not remain one long. mr. fane must know her, since only he had the latch-key."

"yes. only he has----" here laura broke off and flashed an inquiring look on the inspector. "do you mean to say that my brother-in-law knows something about this crime?"

"if only he has the latch-key----"

"you stated that this young man with a pointed beard met by your policeman had a latch-key."

"yes. but has mr. fane a beard?"

"a beard? no. he is clean-shaven."

"he might have assumed a disguise."

"how dare you hint at such a thing?" said laura indignantly. "i am quite sure that mr. fane knows nothing. last night he was at westcliff-on-sea, ill in bed. i can show you a wire. my sister knew that i was going to her to-morrow, and she wired last night at five o'clock saying that walter was ill and that i had better not come."

"oh!" this statement took the inspector aback. if fane had been ill at westcliff-on-sea, he certainly could not be the man met by mulligan. "can you show me the wire?" he asked.

"i will send it round to you. and i am quite sure that when you see mr. fane you will not suspect him of this crime. a better and more kindly man does not live. however this woman came to enter the house, however she was killed, and for what reason, mr. fane can know nothing of the matter. how was she killed?"

"stabbed under the left shoulder-blade while she was singing."

"singing! what was she singing, and why in a strange house?"

"she was singing 'kathleen mavourneen.'"

laura looked surprised. "my sister's favourite song."

"oh indeed," said derrick sharply. he hesitated. "your sister is also at westcliff-on-sea?"

"are you about to accuse her?" asked laura disdainfully.

"i accuse no one," replied derrick, nettled. "i am only trying in all directions to learn facts upon which to build up a theory."

"then why don't you look for real evidence?"

"such as what, miss mason?"

"such as the weapon with which this woman was killed."

"we have looked. it cannot be found. the murderer took it away. he would not be such a fool as to leave that lying about. the doctor fancies from the nature of the wound that it must be a long slim dagger--a kind of stiletto."

"such as a foreigner might use," said laura involuntarily.

"what do you mean?" asked the inspector sharply.

laura flushed. "nothing, nothing," she responded; "but foreigners usually make use of such a weapon, don't they? an englishman would not kill a person with a stiletto."

"it's not british, certainly," said derrick, with insular prejudice; "but a woman might use such a thing. still, we do not know that the assassin is a man or"--he looked straight at her--"a woman."

laura could not quite understand his meaning, since it never struck her that he meant to incriminate her in the matter. she took no notice, being anxious to learn what derrick thought. "what is your theory on existing facts?" she asked coldly.

derrick reflected. "i hardly know what to say. let us suppose that the woman admitted herself into the house. how she got the latch-key i am not prepared to say. she came to meet some one--possibly the two people who killed her."

"the two people?" interrupted laura abruptly.

"there was the young man who kept mulligan in talk," explained the officer, "and the one who presumably killed her. let us suppose, for the sake of argument, that this woman met these two men. seeing a policeman at the gate, number one goes out to lure him away. left alone with number two, the woman sits at the piano to sing. on the music-stand is 'kathleen mavourneen.' she knows that song and sings it. the assassin, standing behind her, watches his opportunity and stabs her. then he goes."

"you forget that the song was being sung, according to your own account, before number one left the gate with the policeman."

"certainly. but the woman might have begun to sing immediately after number one left."

"before," insisted laura. "the policeman listened while number one was in the room. it was the song that made him stop. i am only going by what you told me. your theory doesn't fit together."

derrick frowned. "it is hard to put the pieces of the puzzle together, miss mason. only in detective fiction does the heaven-born genius put this and that together in a flash. i--a mere mortal--am groping in the dark. i may discuss a hundred theories before i hit on the right solution. nothing more can be done till i see mr. fane. as the woman was in his house, he must know----"

"he knows nothing," interrupted laura imperiously; "he can't know. the man is ill at the seaside and----"

derrick interrupted in his turn. "i'll wait till i hear what mr. fane has to say," he declared abruptly.

he rose to terminate the interview. as he opened the door tracey entered hurriedly. "my car's found," he burst out.

"where?" asked derrick and laura together.

"stranded in the yard of charing cross station."

laura turned quickly on derrick. "i beg you to observe, mr. inspector, that you cannot get to westcliff-on-sea from charing cross."

"i have not yet accused mr. fane," retorted the inspector.