"AS you know, Markham," Vance began, when we were seated about the library fire late that night, "I finally succeeded in putting together the items of my summary in such a way that I could see plainly who the murderer was.[29] Once I had found the basic pattern, every detail fitted perfectly into a plastic whole. The technique of the crimes, however, remained obscure; so I asked you to send for the books in Tobias's library—I was sure they would tell me what I wanted to know. First, I went through Gross's 'Handbuch fur Untersuchungsrichter,' which I regarded as the most likely source of information. It is an amazing treatise, Markham. It covers the entire field of the history and science of crime; and, in addition, is a compendium of criminal technique, citing specific cases and containing detailed explanations and diagrams. Small wonder it is the world's standard cyclopaedia on its subject. As I read it, I found what I was looking for. Ada had copied every act of hers, every method, every device, every detail, from its pages—from actual criminal history! We are hardly to be blamed for our inability to combat her schemes; for it was not she alone who was deceiving us; it was the accumulated experience of hundreds of shrewd criminals before her, plus the analytic science of the world's greatest criminologist Doctor Hans Gross."

    He paused to light another cigarette.

    "But even when I had found the explanation of her crimes," he continued, "I felt that there was something lacking, some fundamental penchant— the thing that made this orgy of horror possible and gave viability, so to speak, to her operations. We knew nothing of Ada's early life or of her progenitors and inherited instincts; and without that knowledge the crimes, despite their clear logic, were incredible. Consequently, my next step was to verify Ada's psychological and environmental sources. I had had a suspicion from the first that she was Frau Mannheim's daughter. But even when I verified this fact I couldn't see its bearing on the case. It was obvious, from our interview with Frau Mannheim, that Tobias and her husband had been in shady deals together in the old days; and she later admitted to me that her husband had died thirteen years ago, in October, at New Orleans after a year's illness in a hospital. She also said, as you may recall, that she had seen Tobias a year prior to her husband's death. This would have been fourteen years ago—just the time Ada was adopted by Tobias. I thought there might be some connection between Mannheim and the crimes, and I even toyed with the idea that Sproot was Mannheim, and that a dirty thread of blackmail ran through the situation. So I decided to investigate. My mysterious trip last week was to New Orleans; and there I had no difficulty in learning the truth. By looking up the death records for October thirteen years ago, I discovered that Mannheim had been in an asylum for the criminally insane for a year preceding his death. And from the police I ascertained something of his record. Adolph Mannheim—Ada's father—was, it seems, a famous German criminal and murderer, who had been sentenced to death, but had escaped from the penitentiary at Stuttgart and come to America. I have a suspicion that the departed Tobias was, in some way, mixed up in that escape. But whether or not I wrong him, the fact remains that Ada's father was homicidal and a professional criminal. And therein lies the explanat'ry background of her actions..."

    "You mean she was crazy like her old man?" asked Heath.

    "No, Sergeant. I merely mean that the potentialities of criminality had been handed down to her in her blood. When the motive for the crimes became powerful, her inherited instincts asserted themselves."

    "But mere money," put in Markham, "seems hardly a strong enough motive to inspire such atrocities as hers."

    "It wasn't money alone that inspired her. The real motive went much deeper. Indeed, it was perhaps the most powerful of all human motives—a strange, terrible combination of hate and love and jealousy and a desire for freedom. To begin with, she was the Cinderella in that abnormal Greene family, looked down upon, treated like a servant, made to spend her time caring for a nagging invalid, and forced—as Sibella put it—to earn her livelihood. Can you not see her for fourteen years brooding over this treatment, nourishing her resentment, absorbing the poison about her, and coming at length to despise everyone in that household? That alone would have been enough to awaken her congenital instincts. One almost wonders that she did not break forth long before. But another equally potent element entered the situation. She fell in love with Von Blon—a natural thing for a girl in her position to do—and then learned that Sibella had won his affections. She either knew or strongly suspected that they were married; and her normal hatred of her sister was augmented by a vicious and eroding jealousy...

    "Now, Ada was the only member of the family who, according to the terms of old Tobias's will, was not compelled to live on the estate in event of marriage and in this fact she saw a chance to snatch all the things she craved and at the same time to rid herself of the persons against whom her whole passionate nature cried out in deadly hatred. She calculated to get rid of the family, inherit the Greene millions, and set her cap for Von Blon. There was vengeance, too, as a motivating factor in all this; but I'm inclined to think the amatory phase of the affair was the prim'ry actuating force in the series of horrors she later perpetrated. It gave her strength and courage; it lifted her into that ecstatic realm where everything seemed possible, and where she was willing to pay any price for the desired end. And there is one point I might recall parenthetically—you remember that Barton, the younger maid, told us how Ada sometimes acted like a devil and used vile language. That fact should have given me a hint; but who could have taken Barton seriously at that stage of the game? ...

    "To trace the origin of her diabolical scheme we must first consider the locked library. Alone in the house, bored, resentful, tied down—it was inevitable that this pervertedly romantic child should play Pandora. She had every opportunity of securing the key and having a duplicate made; and so the library became her retreat, her escape from the gruelling, monotonous routine of her existence. There she ran across those books on criminology. They appealed to her, not only as a vicious outlet for her smouldering, repressed hatred, but because they struck a responsive chord in her tainted nature. Eventually she came upon Gross's great manual, and thus found the entire technique of crime laid out before her, with diagrams and examples—not a handbook for examining magistrates, but a guide for a potential murderer! Slowly the idea of her gory orgy took shape. At first perhaps she only imagined, as a means of self- gratification, the application of this technique of murder to those she hated. But after a time, no doubt, the conception became real. She saw its practical possibilities; and the terrible plot was formulated. She created this horror, and then, with her diseased imagination, she came to believe in it. Her plausible stories to us, her superb acting, her clever deceptions—all were part of this horrible fantasy she had engendered. That book of Grimms' 'Fairy Tales'!—I should have understood. Y' see, it wasn't histrionism altogether on her part; it was a kind of demoniac possession. She lived her dream. Many young girls are like that under the stress of ambition and hatred. Constance Kent completely deceived the whole of Scotland Yard into believing in her innocence."

    Vance smoked a moment thoughtfully.

    "It's curious how we instinctively close our eyes to the truth when history is filled with substantiating examples of the very thing we are contemplating. The annals of crime contain numerous instances of girls in Ada's position who have been guilty of atrocious crimes. Besides the famous case of Constance Kent, there were, for example, Marie Boyer, and Madeliene Smith, and Grete Beyer. I wonder if we'd have suspected them."[30]

    "Keep to the present, Vance," interposed Markham impatiently. "You say Ada took all her ideas from Gross. But Gross's handbook is written in German. How did you know she spoke German well enough—?"

    "That Sunday when I went to the house with Van I inquired of Ada if Sibella spoke German. I put my questions in such a way that she could not answer without telling me whether or not she, too, knew German well. Incidentally, I wanted her to think that I suspected Sibella, so that she would not hasten matters until I returned from New Orleans. I knew that as long as Sibella was in Atlantic City she was safe from Ada."

    "But what I want to know," put in Heath, "is how she killed Rex when she was sitting in Mr. Markham's office."

    "Let us take things in order, Sergeant," answered Vance. "Julia was killed first because she was the manager of the establishment. With her out of the way, Ada would have a free hand. And, another thing, the death of Julia at the start fitted best into the scheme she had outlined; it gave her the most plausible setting for staging the attempted murder on herself. Ada had undoubtedly heard some mention of Chester's revolver, and after she had secured it she waited for the opportunity to strike the first blow. The propitious circumstances fell on the night of November 8th; and at half past eleven, when the house was asleep, she knocked on Julia's door. She was admitted, and doubtless sat on the edge of Julia's bed telling some story to explain her late visit. Then she drew the gun from under her dressing-gown and shot Julia through the heart. Back in her own bedroom, with the lights on, she stood before the large mirror of the dressing-table, and, holding the gun in her right hand, placed it against her left shoulder-blade at an oblique angle. The mirror and the lights were essential, for she could thus see exactly where to point the muzzle of the revolver. All this occupied the three-minute interval between the shots. Then she pulled the trigger—"

    "But a girl shooting herself as a fake!" objected Heath. "It ain't natural."

    "But Ada wasn't natural, Sergeant. None of the plot was natural. That was why I was so anxious to look up her family history. But as to shooting herself; that was quite logical when one considers her true character. And, as a matter of fact, there was little or no danger attaching to it. The gun was on a hair-trigger, and no pressure was needed to discharge it. A slight flesh wound was the worst she had to fear. Moreover, history is full of cases of self-mutilation where the object to be gained was far smaller than what Ada was after. Gross is full of them..."

    He took up Volume I of the "Handbuch für Untersuchungsrichter," which lay on the table beside him, and opened it at a marked page.

    "Listen to this, Sergeant. I'll translate the passage roughly as I read: 'It is not uncommon to find people who inflict wounds upon themselves; such are, besides persons pretending to be the victims of assaults with deadly weapons, those who try to extort damages or blackmailers. Thus it often happens that, after an insignificant scuffle, one of the combatants shows wounds which he pretends to have received. It is characteristic of these voluntary mutilations that most frequently those who perform them do not quite complete the operation, and that they are for the most part people who manifest excessive piety, or lead a solitary life.'[31] ...And surely, Sergeant, you are familiar with the self- mutilation of soldiers to escape service. The most common method used by them is to place their hand over the muzzle of the gun and blow their fingers off."

    Vance closed the book.

    "And don't forget that the girl was hopeless, desperate, and unhappy, with everything to win and nothing to lose. She would probably have committed suicide if she had not worked out the plan of the murders. A superficial wound in the shoulder meant little to her in view of what she was to gain by it. And women have an almost infinite capacity for self- immolation. With Ada, it was part of her abnormal condition. No, Sergeant; the self-shooting was perfectly consistent in the circumstances..."

    "But in the back!" Heath looked dumbfounded. "That's what gets me. Whoever heard—?"

    "Just a moment." Vance took up Volume II of the "Handbuch" and opened it to a marked page. "Gross, for instance, has heard of many such cases—in fact, they're quite common on the Continent. And his record of them indubitably gave Ada the idea for shooting herself in the back. Here's a single paragraph culled from many pages of similar cases: 'That you should not be deceived by the seat of the wound is proved by the following two cases. In the Vienna Prater a man killed himself in the presence of several people by shooting himself in the back of the head with a revolver. Without the testimony of several witnesses nobody would have accepted the theory of suicide. A soldier killed himself by a shot with his military rifle through the back, by fixing the rifle in a certain position and then lying down over it. Here again 'the position of the wound seemed to exclude the theory of suicide.'"[32]

    "Wait a minute!" Heath heaved himself forward and shook his cigar at Vance. "What about the gun? Sproot entered Ada's room right after the shot was fired, and there wasn't no sign of a gun!"

    Vance, without answering, merely turned the pages of Gross's "Handbuch" to where another marker protruded, and began translating:

    "'Early one morning the authorities were informed that the corpse of a murdered man had been found. At the spot indicated the body was discovered of a grain merchant, A. M., supposed to be a well-to-do man, face downward with a gunshot wound behind his ear. The bullet, after passing through the brain, had lodged in the frontal bone above the left eye. The place where the corpse was found was in the middle of a bridge over a deep stream. Just when the inquiry was concluding and the corpse was about to be removed for the post-mortem, the investigating officer observed quite by chance that on the decayed wooden parapet of the bridge, almost opposite to the spot where the corpse lay, there was a small but perfectly fresh dent which appeared to have been caused by a violent blow on the upper edge of the parapet of a hard and angular object. He immediately suspected that the dent had some connection with the murder. Accordingly he determined to drag the bed of the stream below the bridge, when almost immediately there was picked up a strong cord about fourteen feet long with a large stone at one end and at the other a discharged pistol, the barrel of which fitted exactly the bullet extracted from the head of A. M. The case was thus evidently one of suicide. A. M. had hung the stone over the parapet of the bridge and discharged the pistol behind his ear. The moment he fired he let go the pistol, which the weight of the stone dragged over the parapet into the water.'[33] ... Does that answer your question, Sergeant?"

    Heath stared at him with gaping eyes.

    "You mean her gun went outa the window the same like that guy's gun went over the bridge?"

    "There can be no doubt about it. There was no other place for the gun to go. The window, I learned from Sproot, was open a foot, and Ada stood before the window when she shot herself. Returning from Julia's room she attached a cord to the revolver with a weight of some kind on the other end, and hung the weight out of the window. When her hand released the weapon it was simply drawn over the sill and disappeared in the drift of soft snow on the balcony steps. And there is where the importance of the weather came in. Ada's plan needed an unusual amount of snow; and the night of November 8th was ideal for her grisly purpose."

    "My God, Vance" Markham's tone was strained and unnatural. "This thing begins to sound more like a fantastic nightmare than a reality."

    "Not only was it a reality, Markham," said Vance gravely, "but it was an actual duplication of reality. It had all been done before and duly recorded in Gross's treatise, with names, dates, and details."

    "Hell No wonder we couldn't find the gun." Heath spoke with awed disgust. "And what about the footprints, Mr. Vance? I suppose she faked 'em all."

    "Yes, Sergeant—with Gross's minute instructions and the footprint forgeries of many famous criminals to guide her, she faked them. As soon as it had stopped snowing that night she slipped downstairs, put on a pair of Chester's discarded galoshes, and walked to the front gate and back. Then she hid the galoshes in the library."

    Vance turned once more to Gross's manual.

    "There's everything here that one could possibly want to know about the making and detection of footprints, and—what is more to the point—about the manufacturing of footprints in shoes too large for one's feet.—Let me translate a short passage: 'The criminal may intend to cast suspicion upon another person, especially if he foresees that suspicion may fall upon himself. In this case he produces clear footprints which, so to speak, leap to the eyes, by wearing shoes which differ essentially from his own. One may often in this way, as has been proved by numerous experiments, produce footprints which deceive perfectly.'[34] ... And here at the end of the paragraph, Gross refers specifically to galoshes[35]—a fact which very likely gave Ada her inspiration to use Chester's overshoes. She was shrewd enough to profit by the suggestions in this passage."

    "And she was shrewd enough to hoodwink all of us when we questioned her," commented Markham bitterly.

    "True. But that was because she had a folie de grandeur, and lived the story. Moreover, it was all based on fact; its details were grounded in reality. Even the shuffling sound she said she heard in her room was an imaginative projection of the actual shuffling sound she made when she walked in Chester's huge galoshes. Also, her own shuffling, no doubt, suggested to her how Mrs. Greene's footsteps would have sounded had the old lady regained the use of her legs. And I imagine it was Ada's original purpose to cast a certain amount of suspicion on Mrs. Greene from the very beginning. But Sibella's attitude during that first interview caused her to change her tactics. As I see it, Sibella was suspicious of little sister, and talked the situation over with Chester, who may also have had misgivings about Ada. You remember his sub-rosa chat with Sibella when he went to summon her to the drawing-room. He was probably informing her that he hadn't yet made an accusation against Ada, and was advising her to go easy until there was some specific proof. Sibella evidently agreed, and refrained from any direct charge until Ada, in telling her grotesque fairy-tale about the intruder, rather implied it was a woman's hand that had touched her in the dark. That was too much for Sibella, who thought Ada was referring to her; and she burst forth with her accusation, despite its seeming absurdity. The amazing thing about it was that it happened to be the truth. She named the murderer and stated a large part of the motive before any of us remotely guessed the truth, even though she did back down and change her mind when the inconsistency of it was pointed out to her. And she really did see Ada in Chester's room looking for the revolver."

    Markham nodded.

    "It's astonishing. But after the accusation, when Ada knew that Sibella suspected her, why didn't she kill Sibella next?"

    "She was too canny. It would have tended to give weight to Sibella's accusations. Oh, Ada played her hand perfectly."

    "Go on with the story, sir," urged Heath, intolerant of these side issues.

    "Very well, Sergeant." Vance shifted more comfortably into his chair. "But first we must revert to the weather; for the weather ran like a sinister motif through all that followed. The second night after Julia's death it was quite warm, and the snow had melted considerably. That was the night chosen by Ada to retrieve the gun. A wound like hers rarely keeps one in bed over forty-eight hours; and Ada was well enough on Wednesday night to slip into a coat, step out on the balcony, and walk down the few steps to where the gun lay hidden. She merely brought it back and took it to bed with her—the last place anyone would have thought to look for it. Then she waited patiently for the snow to fall again—which it did the next night, stopping, as you may remember, about eleven o'clock. The stage was set. The second act of the tragedy was about to begin...

    "Ada rose quietly, put on her coat, and went down to the library. Getting into the galoshes, she again walked to the front gate and back. Then she went directly upstairs so that her tracks would show on the marble steps, and hid the galoshes temporarily in the linen-closet. That was the shuffling sound and the closing door that Rex heard a few minutes before Chester was shot. Ada, you recall, told us afterwards she had heard nothing; but when we repeated Rex's story to her she became frightened and conveniently remembered having heard a door close. My word! That was a ticklish moment for her. But she certainly carried it off well. And I can now understand her obvious relief when we showed her the pattern of the footprints and let her think we believed the murderer came from outside... Well, after she had removed the galoshes and put them in the linen-closet, she took off her coat, donned a dressing-gown, and went to Chester's room—probably opened the door without knocking, and went in with a friendly greeting. I picture her as sitting on the arm of Chester's chair, or the edge of the desk, and then, in the midst of some trivial remark, drawing the revolver, placing it against his breast, and pulling the trigger before he had time to recover from his horrified astonishment. He moved instinctively, though, just as the weapon exploded—which would account for the diagonal course of the bullet. Then Ada returned quickly to her own room and got into bed. Thus was another chapter written in the Greene tragedy."

    "Did it strike you as strange," asked Markham, "that Von Blon was not at his office during the commission of either of the crimes?"

    "At first—yes. But, after all, there was nothing unusual in the fact that a doctor should have been out at that time of night."

    "It's easy enough to see how Ada got rid of Julia and Chester," grumbled Heath. "But what stops me is how she murdered Rex."

    "Really, y' know, Sergeant," returned Vance, "that trick of hers shouldn't cause you any perplexity. I'll never forgive myself for not having guessed it long ago—Ada certainly gave us enough clues to work on. But, before I describe it to you, let me recall a certain architectural detail of the Greene mansion. There is a Tudor fire-place, with carved wooden panels, in Ada's room, and another fire-place—a duplicate of Ada's in Rex's room; and these two fire-places are back to back on the same wall. The Greene house, as you know, is very old, and at some time in the past—perhaps when the fire-places were built—an aperture was made between the two rooms, running from one of the panels in Ada's mantel to the corresponding panel in Rex's mantel. This miniature tunnel is about six inches square—the exact size of the panels—and a little over two feet long, or the depth of the two mantels and the wall. It was originally used, I imagine, for private communication between the two rooms. But that point is immaterial. The fact remains that such a shaft exists—I verified it to-night on my way down-town from the hospital. I might also add that the panel at either end of the shaft is on a spring hinge, so that when it is opened and released it closes automatically, snapping back into place without giving any indication that it is anything more than a solid part of the woodwork—"

    "I get you!" exclaimed Heath, with the excitement of satisfaction. "Rex was shot by the old man-killing safe idea: the burglar opens the safe door and gets a bullet in his head from a stationary gun."

    "Exactly. And the same device has been used in scores of murders. In the early days out West an enemy would go to a rancher's cabin during the tenant's absence, hang a shot-gun from the ceiling over the door, and tie one end of a string to the trigger and the other end to the latch. When the rancher returned—perhaps days later—his brains would be blown out as he entered his cabin; and the murderer would, at the time, be in another part of the country."

    "Sure!" The sergeant's eyes sparkled. "There was a shooting like that in Atlanta two years ago—Boscomb was the name of the murdered man. And in Richmond, Va."

    "There have been many instances of it, Sergeant. Gross quotes two famous Austrian cases, and also has something to say about this method in general."

    Again he opened the "Handbuch."

    "On page 943 Gross remarks: 'The latest American safety devices have nothing to do with the safe itself, and can in fact be used with any receptacle. They act through chemicals or automatic firing devices, and their object is to make the presence of a human being who illegally opens the safe impossible on physical grounds. The judicial question would have to be decided whether one is legally entitled to kill a burglar without further ado or damage his health. However, a burglar in Berlin in 1902 was shot through the forehead by a self-shooter attached to a safe in an exporting house. This style of self-shooter has also been used by murderers. A mechanic, G. Z., attached a pistol in a china-closet, fastening the trigger to the catch, and thus shot his wife when he himself was in another city. R. C., a merchant of Budapest, secured a revolver in a humidor belonging to his brother, which, when the lid was opened, fired and sent a bullet into his brother's abdomen. The explosion jerked the box from the table, and thus exposed the mechanism before the merchant had a chance to remove it.'[36] ... In both these latter cases Gross gives a detailed description of the mechanisms employed. And it will interest you, Sergeant—in view of what I am about to tell you—to know that the revolver in the china-closet was held in place by a Stiefelknecht, or bootjack."

    He closed the volume, but held it on his lap.

    "There, unquestionably, is where Ada got the suggestion for Rex's murder. She and Rex had probably discovered the hidden passage-way between their rooms years ago. I imagine that as children—they were about the same age, don't y' know—they used it as a secret means of correspondence. This would account for the name by which they both knew it—'our private mailbox.' And, given this knowledge between Ada and Rex, the method of the murder becomes perfectly clear. To-night I found an old-fashioned boot-jack in Ada's clothes-closet—probably taken from Tobias's library. Its width, over-all, was just six inches, and it was a little less than two feet long—it fitted perfectly into the communicating cupboard. Ada, following Gross's diagram, pressed the handle of the gun tightly between the tapering claws of the bootjack, which would have held it like a vice; then tied a string to the trigger, and attached the other end to the inside of Rex's panel, so that when the panel was opened wide the revolver, being on a hair trigger, would discharge straight along the shaft and inevitably kill anyone looking into the opening. When Rex fell with a bullet in his forehead the panel flapped back into place on its spring hinge; and a second later there was no visible evidence whatever pointing to the origin of the shot. And here we also have the explanation for Rex's calm expression of unawareness. When Ada returned with us from the District Attorney's office, she went directly to her room, removed the gun and the bootjack, hid them in her closet, and came down to the drawing-room to report the foot-tracks on her carpet—foot-tracks she herself had made before leaving the house. It was just before she came downstairs, by the way, that she stole the morphine and strychnine from Von Blon's case."

    "But, my God, Vance!" said Markham. "Suppose her mechanism had failed to work. She would have been in for it then."

    "I hardly think so. If, by any remote chance, the trap had not operated or Rex had recovered, she could easily have put the blame on someone else. She had merely to say she had secreted the diagram in the chute and that this other person had prepared the trap later on. There would have been no proof of her having set the gun."

    "What about that diagram, sir?" asked Heath.

    For answer Vance again took up the second volume of Gross and, opening it, extended it toward us. On the right-hand page were a number of curious line-drawings.

    "There are the three stones, and the parrot, and the heart, and even your arrow, Sergeant. They're all criminal graphic symbols; and Ada simply utilized them in her description. The story of her finding the paper in the hall was a pure fabrication, but she knew it would pique our curiosity. The truth is, I suspected the paper of being faked by someone, for it evidently contained the signs of several types of criminal, and the symbols were meaninglessly jumbled. I rather imagined it was a false clue deliberately placed in the hall for us to find—like the footprints; but I certainly didn't suspect Ada of having made up the tale. Now, however, as I look back at the episode it strikes me as deuced queer that she shouldn't have brought so apparently significant a paper to the office. Her failure to do so was neither logical nor reasonable; and I ought to have been suspicious. But—my word!—what was one illogical item more or less in such a mélange of inconsistencies? As it happened, her decoy worked beautifully, and gave her the opportunity to telephone Rex to look into the chute. But it didn't really matter. If the scheme had fallen through that morning, it would have been successful later on. Ada was highly persevering."

    "You think, then," put in Markham, "that Rex really heard the shot in Ada's room that first night, and confided in her?"

    "Undoubtedly. That part of her story was true enough. I'm inclined to think that Rex heard the shot and had a vague idea Mrs. Greene had fired it. Being rather close to his mother temperamentally, he said nothing. Later he voiced his suspicions to Ada; and that confession gave her the idea for killing him—or, rather, for perfecting the technique she had already decided on; for Rex would have been shot through the secret cupboard in any event. But Ada now saw a way of establishing a perfect alibi for the occasion; although even her idea of being actually with the police when the shot was fired was not original. In Gross's chapter on alibis there is much suggestive material along that line."

    Heath sucked his teeth wonderingly.

    "I'm glad I don't run across many of her kind," he remarked.

    "She was her father's daughter," said Vance. "But too much credit should not be given to her, Sergeant. She had a printed and diagrammed guide for everything. There was little for her to do but follow instructions and keep her head. And as for Rex's murder, don't forget that, although she was actually in Mr. Markham's office at the time of the shooting, she personally engineered the entire coup. Think back. She refused to let either you or Mr. Markham come to the house, and insisted upon visiting the office. Once there, she told her story and suggested that Rex be summoned immediately. She even went so far as to plead with us to call him by phone. Then, when we had complied, she quickly informed us of the mysterious diagram, and offered to tell Rex exactly where she had hidden it, so he could bring it with him. And we sat there calmly, listening to her send Rex to his death! Her actions at the Stock Exchange should have given me a hint; but I confess I was particularly blind that morning. She was in a state of high nervous excitement; and when she broke down and sobbed on Mr. Markham's desk after he had told her of Rex's death, her tears were quite real—only, they were not for Rex; they were the reaction from that hour of terrific tension."

    "I begin to understand why no one upstairs heard the shot," said Markham. "The revolver detonating in the wall, as it were, would have been almost completely muffled, But why should Sproot have heard it so distinctly downstairs?"

    "You remember there was a fire-place in the living-room directly beneath Ada's—Chester once told us it was rarely lighted because it wouldn't draw properly—and Sproot was in the butler's pantry just beyond. The sound of the report went downward through the flue and, as a result, was heard plainly on the lower floor."

    "You said a minute ago, Mr. Vance," argued Heath, "that Rex maybe suspected the old lady. Then why should he have accused Von Blon the way he did that day he had a fit?"

    "The accusation primarily, I think, was a sort of instinctive effort to drive the idea of Mrs. Greene's guilt from his own mind. Then, again, as Von Blon explained, Rex was frightened after you had questioned him about the revolver, and wanted to divert suspicion from himself."

    "Get on with the story of Ada's plot, Vance." This time it was Markham who was impatient.

    "The rest seems pretty obvious, don't y' know. It was unquestionably Ada who was listening at the library door the afternoon we were there. She realized we had found the books and galoshes; and she had to think fast. So, when we came out, she told us the dramatic yarn of having seen her mother walking, which was sheer moonshine. She had run across those books on paralysis, d' ye see, and they had suggested to her the possibility of focusing suspicion on Mrs. Greene—the chief object of her hate. It is probably true, as Von Blon said, that the two books do not deal with actual hysterical paralysis and somnambulism, but they no doubt contain references to these types of paralysis. I rather think Ada had intended all along to kill the old lady last and have it appear as the suicide of the murderer. But the proposed examination by Oppenheimer changed all that. She learned of the examination when she heard Von Blon apprise Mrs. Greene of it on his morning visit; and, having told us of that mythical midnight promenade, she couldn't delay matters any longer. The old lady had to die—before Oppenheimer arrived. And half an hour later Ada took the morphine. She feared to give Mrs. Greene the strychnine at once lest it appear suspicious..."

    "That's where those books on poisons come in, isn't it, Mr. Vance?" interjected Heath. "When Ada had decided to use poison on some of the family, she got all the dope she needed on the subject outa the library."

    "Precisely. She herself took just enough morphine to render her unconscious-probably about two grains. And to make sure she would get immediate assistance she devised the simple trick of having Sibella's dog appear to give the alarm. Incidentally, this trick cast suspicion on Sibella. After Ada had swallowed the morphine, she merely waited until she began to feel drowsy, pulled the bell-cord, caught the tassel in the dog's teeth, and lay back. She counterfeited a good deal of her illness; but Drumm couldn't have detected her malingering even if he had been as great a doctor as he wanted us to believe; for the symptoms for all doses of morphine taken by mouth are practically the same during the first half-hour. And, once she was on her feet, she had only to watch for an opportunity of giving the strychnine to Mrs. Greene..."

    "It all seems too cold-blooded to be real," murmured Markham.

    "And yet there has been any number of precedents for Ada's actions. Do you recall the mass murders of those three nurses, Madame Jegado, Frau Zwanzigger, and Vrouw Van der Linden? And there was Mrs. Belle Gunness, the female Bluebeard; and Amelia Elizabeth Dyer, the Reading baby-farmer; and Mrs. Pearcey. Cold-blooded? Yes! But in Ada's case there was passion too. I'm inclined to believe that it takes a particularly hot flame—a fire at white heat, in fact—to carry the human heart through such a Gethsemane. However that may be, Ada watched for her chance to poison Mrs. Greene, and found it that night. The nurse went to the third floor to prepare for bed between eleven and eleven-thirty; and during that half-hour Ada visited her mother's room. Whether she suggested the citro- carbonate or Mrs. Greene herself asked for it, we'll never know. Probably the former, for Ada had always given it to her at night. When the nurse came downstairs again Ada was already back in bed, apparently asleep, and Mrs. Greene was on the verge of her first—and, let us hope, her only— convulsion."

    "Doremus's post-mortem report must have given her a terrific shock," commented Markham.

    "It did. It upset all her calculations. Imagine her feelings when we informed her that Mrs. Greene couldn't have walked! She backed out of the danger nicely, though. The detail of the Oriental shawl, however, nearly entangled her. But even that point she turned to her own advantage by using it as a clue against Sibella."

    "How do you account for Mrs. Mannheim's actions during that interview?" asked Markham. "You remember her saying it might have been she whom Ada saw in the hall."

    A cloud came over Vance's face.

    "I think," he said sadly, "that Frau Mannheim began to suspect her little Ada at that point. She knew the terrible history of the girl's father, and perhaps had lived in fear of some criminal outcropping in the child."

    There was a silence for several moments. Each of us was busy with his own thoughts. Then Vance continued:

    "After Mrs. Greene's death, only Sibella stood between Ada and her blazing goal; and it was Sibella herself who gave her the idea for a supposedly safe way to commit the final murder. Weeks ago, on a ride Van and I took with the two girls and Von Blon, Sibella's venomous pique led her to make a foolish remark about running one's victim over a precipice in a machine; and it no doubt appealed to Ada's sense of the fitness of things that Sibella should thus suggest the means of her own demise. I wouldn't be at all surprised if Ada intended, after having killed her sister, to say that Sibella had tried to murder her, but that she had suspected the other's purpose and jumped from the car in time to save herself; and that Sibella had miscalculated the car's speed and been carried over the precipice. The fact that Von Blon and Van and I had heard Sibella speculate on just such a method of murder would have given weight to Ada's story. And what a neat ending it would have made— Sibella, the murderer, dead; the case closed; Ada, the inheritor of the Greene millions, free to do as she chose! And—'pon my soul, Markham!—it came very near succeeding."

    Vance sighed, and reached for the decanter. After refilling our glasses, he settled back and smoked moodily.

    "I wonder how long this terrible plot had been in preparation. We'll never know. Maybe years. There was no haste in Ada's preparations. Everything was worked out carefully; and she let circumstances—or, rather, opportunity—guide her. Once she had secured the revolver, it was only a question of waiting for a chance when she could make the footprints and be sure the gun would sink out of sight in the snow-drift on the balcony steps. Yes, the most essential condition of her scheme was the snow! ...Amazin'!"

    There is little more to add to this record. The truth was not given out, and the case was "shelved." The following year Tobias's will was upset by the Supreme Court in Equity—that is, the twenty-five-year domiciliary clause was abrogated in view of all that had happened at the house; and Sibella came into the entire Greene fortune. How much Markham had to do with the decision, through his influence with the Administration judge who rendered it, I don't know; and naturally I have never asked. But the old Greene mansion was, as you remember, torn down shortly afterward, and the estate sold to a realty corporation.

    Mrs. Mannheim, broken-hearted over Ada's death, claimed her inheritance— which Sibella generously doubled—and returned to Germany to seek what comfort she might among the nieces and nephews with whom, according to Chester, she was constantly corresponding. Sproot went back to England. He told Vance before departing that he had long planned a cottage retreat in Surrey where he could loaf and invite his soul. I picture him now, sitting in an ivied porch overlooking Kew Gardens, reading his beloved Martial.

    Doctor and Mrs. Von Blon, immediately after the court's decision relating to the will, sailed for the Riviera and spent a year's belated honeymoon there. They are now settled in Vienna, where the doctor has become a Docent at the University—his father's Alma Mater. He is, I understand, making quite a name for himself in the field of neurology.

    One domestic item may be appended. Several months ago a friend of mine, returning from Vienna, brought me the news that Sibella had given birth to a son and heir. The fact, I admit, struck me as somewhat incongruous. It is difficult for me to picture Sibella in the rôle of mother. But, as one of our leading sociologists recently assured us, the modern girl harbours beneath her callous and highly sophisticated exterior an intense, age-old maternalism. "Indeed," added this eminent sociologist, "the modern girls make the best mothers." Let us sincerely hope that Sibella will confirm his generous optimism.