blenkinsop's sudden announcement, not altogether unexpected by hetherwick as a result of the last few minutes' proceedings, seemed to strike matherfield with all the force of a lightning-like illumination. his mouth opened; his eyes widened; he turned on hetherwick as if, having been lost for a while in a baffling maze, he had suddenly seen a way pointed out to him.

"oh, that's it, is it?" he exclaimed. "a twin sister, eh? then—but go on, mr. blenkinsop; i'm beginning to see things."

"the matter is doubtless puzzling—to outsiders," responded blenkinsop. "to clear it up, i shall have to go into some family history. lady riversreade and madame listorelle are, i repeat, twin sisters. they are the daughters of a man who in his time was captain of various merchant ships—the old sailing ships—and who knocked about the world a good deal. he married an american woman, and his two daughters were born in galveston, texas. they were educated in america—but there's no need to go into the particulars of their early lives——"

"there's a certain particular that i should like to have some information about, if you please," interrupted hetherwick. "the mrs. whittingham who was at sellithwaite ten years ago had the figure of a snake tattooed round a wrist, in various colours. she wore a black velvet band to cover it. now——"

blenkinsop turned to his partner with a smile.

"i thought that would come up," he said. "well mr. hetherwick, if you want to know about that matter, both sisters are tattooed in the same fashion. that was a bit of work of the old sea-dog, their father—a fancy, and a very foolish one, of his. he had the children tattooed in that way when they were quite young, much to their disgust when they grew older. each lady wears a covering velvet armlet—as i know."

"proceed, if you please," said hetherwick. "that's cleared up!"

"i gather that you've been making inquiries on your own account," observed blenkinsop. "well, since we're determined to tell you everything, we'll be as good as our word. so let's come to the sellithwaite affair. you've probably heard only one version—you may have got it from hannaford; you may have got it from old newspapers; you may have got it on the spot—it's immaterial to us. but you haven't heard the version of the lady who was then mrs. whittingham. that puts a rather different complexion on things. for reasons of her own, with which we've nothing to do, mrs. whittingham—her proper and legal name at that time—stayed at sellithwaite for a while. she had various transactions with a jeweller there; eventually she bought from him a diamond necklace at a price—three thousand nine hundred pounds. she gave him a cheque for the amount, fully expecting that by the time it reached her bankers in manchester certain funds for her credit would have reached them from america. there was a hitch—the funds didn't arrive—the cheque was returned. the jeweller approached the police—hannaford, their superintendent there, got out a warrant and tracked down mrs. whittingham. he arrested her, and she got away from him, left england, and returned to america. for some time she was in financial straits. but she did not forget her liabilities, and eventually she sent the sellithwaite jeweller the agreed price of the diamond necklace, and eight years' interest at five per cent. on the amount. she holds his formal receipt for the money she sent him. so much for that episode—whether hannaford ever knew of the payment or not, i don't know. we are rather inclined to believe that he didn't. but—the necklace was paid for, and paid for handsomely."

"i may as well say that i'm aware of that," remarked hetherwick. "i have been informed of the fact at first hand."

"very good. i see you have been at sellithwaite," said blenkinsop with another of his shrewd smiles. "now then, we come to what is far more pertinent—recent events. the situation as regards lady riversreade and madame listorelle some little time ago—say, when hannaford came to town—was this: lady riversreade, widow of sir john riversreade, had inherited his considerable fortune, was settled at riversreade court in surrey, and had founded a home for wounded officers close by, of which my friend and partner, major penteney there, is london representative. her sister, madame listorelle, had a flat at paddington and another in new york. she was chiefly in new york, but she was sometimes in london and sometimes in paris. as a matter of fact, madame listorelle is an expert in precious stones, and a dealer in them. but she has recently become engaged to be married to a well-known peer, an elderly, very wealthy man—which possibly has a good deal to do with what i am going to tell you."

"probably, i think, blenkinsop—not possibly," suggested penteney. "probably!—decidedly."

"probably, then—probably!" assented blenkinsop. he leaned forward across his desk towards the two listeners. "now, gentlemen, your closest attention, for i'm coming to the really important points of this matter—those that affect the police particularly. about a fortnight ago lady riversreade, being in her private office at her home, close by riversreade court, was waited upon by a man who sent in a card bearing the name of dr. cyprian baseverie. lady riversreade thought that the presenter of this card was some medical man who wished to inspect the home, and he was admitted to see her. she soon found out that he had come on no such errand as she had imagined. he told her a strange tale. he let her know, to begin with, that he was fully conversant with that episode in her sister's life which related to sellithwaite and the diamond necklace. lady riversreade, who knew all about it, felt that the man's information had been gained at first hand. he also let her know that madame listorelle's whereabouts and engagement were familiar to him; in short, he showed that he was well up in the present family history, both as regards lady riversreade and her sister. then he let his hand be seen more plainly. he told lady riversreade that a certain gang of men in london had become acquainted with the facts of the sellithwaite matter, the warrant, the arrest, the escape, and that they were also aware of madame listorelle's engagement to lord—we will leave his name out at present, or refer to him as lord x—and that they wanted a price for their silence. in other words, they were determined on blackmail. if they were not paid their price, they were going to lord x, with all the facts, to tell him that he was engaged to a woman who, as they would put it, was still liable by the law of the land to arrest and prosecution for fraud."

"isn't she?" asked matherfield suddenly. "no time-limit in these sort of cases, i think, mr. blenkinsop. liable ten or twenty or thirty years after—i think!"

"i've already said that the sellithwaite affair was one of account," replied blenkinsop. "there was no intent to defraud, and the full amount and interest on it was duly paid. but that's not the point—we're dealing with the presentment of this to lady riversreade by the man baseverie. of course, lady riversreade didn't know how the law might be, and she was alarmed on her sister's account. she asked baseverie what he wanted. he told her plainly then that he could settle these men—if she would find the money. he had, he said, a certain hold over them which he could use to advantage. lady riversreade wanted to know what that hold was; he wouldn't tell her. she then wanted to know how much the men wanted; he wouldn't say. what he did say was that if she would be prepared to find the money to silence them, he, during the next week, would exert pressure on them to accept a reasonable amount, and would call on her on the following friday and tell her what they would take. she made that appointment with him."

"and, i hope, took advice in the meantime," muttered matherfield. "ought to have handed him over there and then!"

"no—she took no advice in the meantime," continued blenkinsop. "madame listorelle was in paris—major penteney was away on business in the country. lady riversreade awaited baseverie's next coming. when he came he told her what his gang wanted—thirty thousand pounds. he specified, too, the way in which it was to be paid—in a fashion which would have prevented the payment being traced to the people who received it. but now lady riversreade was more prepared—she had had time to think. she expected major penteney next day; she also knew that her sister would return from paris on the following monday. so she told baseverie that she would give him an answer on monday evening if he would make an appointment to meet her at some place in london. eventually they made an appointment at vivian's, in candlestick passage. baseverie went away; next day lady riversreade told major penteney all that had happened. as a result, he went with her to vivian's on monday evening. they waited an hour beyond the fixed time. baseverie made no appearance——"

"just so!" muttered matherfield. "he wouldn't—the major being there!"

"perhaps," assented blenkinsop. "anyway, he didn't materialise. so lady riversreade went away, leaving major penteney behind her. i may say that he stopped there for some further time, keeping a sharp look-out for the man whom lady riversreade had described in detail—a remarkable man in appearance, i understand. but he never saw him."

"no!" exclaimed matherfield cynically. "of course he didn't! but she would ha' done—if she'd gone alone!"

"well, there it was," continued blenkinsop. "now for lady riversreade. she drove to her sister's flat in paddington, and found madame listorelle just returned from paris. she told her all that had happened. madame listorelle determined to go to new york at once and get certain papers from her flat there which would definitely establish her absolute innocence in the sellithwaite affair. leaving lady riversreade in the flat, madame listorelle set off for southampton before five o'clock next morning—yes?"

matherfield, uttering a deep groan, smote his forehead.

"aye!" he muttered. "just so! to be sure! but go on!—go on, sir."

"you seem to be highly surprised," said blenkinsop. "however—at southampton she booked a passage in a name she always used when travelling—her maiden name—by the tartaric, sailing that afternoon. that done, she went to a hotel for lunch. then she began to think things over more calmly. and in the end, instead of sailing for new york, she went back, cancelled her booking, and set off by train to lord x's country seat in wiltshire, and told him the whole story. she wired to her sister as to what she had done, and in the evening wrote to her. meanwhile, lady riversreade had returned, early in the morning, to riversreade court. major penteney went with her. he was confident that baseverie would turn up. he did turn up! but he did not see lady riversreade. he saw major penteney—alone. and major penteney, after a little plain talk to him, metaphorically kicked him out, and told him to do his worst. he went—warned that if ever he showed himself there again he would be handed over to the police."

matherfield groaned again, but the reason of his distress was obviously of a different nature.

"a mistake, sir—a great mistake!" he exclaimed, shaking his head at penteney. "you shouldn't have let that fellow go like that! you should have handed him over there and then. go? you don't know where he may be!"

"oh, well, we're not quite such fools as we seem, matherfield," he replied. "when i went down to dorking with lady riversreade on tuesday morning i had with me a smart man whom i can trust. he saw baseverie arrive; he saw baseverie leave. i think we shall be able to put our fingers on baseverie at any moment. our man won't lose sight of him!"

"oh, well, that's better, sir, that's much better!" said matherfield. "that's all right! a chap like that should be watched night and day. but now, gentlemen, about this reward! your notion of offering it sprang, of course, from this baseverie business. but—how, exactly? did he mention hannaford to lady riversreade?"

"no!" replied blenkinsop. "i'll tell you how we came to issue the advertisement. all sunday afternoon and evening, and for some time on monday morning, lady riversreade, major penteney, and myself were in close consultation about this affair. i'll tell you at once how and why we connected it with the poisoning of hannaford, of which, of course, all of us had read in the newspapers."

"aye!—how, now?" asked matherfield.

"because of this," answered blenkinsop. he tapped his desk to emphasise his words, watching matherfield keenly as he spoke. "because of this: baseverie told lady riversreade that the gang of blackmailers had in their possession the original warrant for mrs. whittingham's arrest!"

hetherwick felt himself impelled to jump in his chair, to exclaim loudly. he repressed the inclination, but matherfield was less reserved.

"ah!" he exclaimed sharply. "ah!"

"baseverie made a false step there," continued blenkinsop. "he should never have told that. but he did—no doubt he thought a rich woman easy prey. now, of course, when we came to consult, we knew all about the sellithwaite affair; we knew, too, that hannaford was superintendent at the time and that he had the warrant; it was not at all improbable that he had preserved it in his pocket-book, and had it on him when he came to london. what, then, was the obvious conclusion—that the men who now held that warrant had got it, probably by foul means, from hannaford, and were concerned in his murder? and—more than that—did the gang of which baseverie spoke really exist? wasn't it likely that the gang was—baseverie?"

"aye!" muttered matherfield. "i've been thinking of that!"

"yet," said blenkinsop, "it was on the cards that there might be a gang. we searched all the newspapers' accounts thoroughly. we found that next to no information could be got as to hannaford's movements between the time of his arrival in london and the night of his death. the one man who might have given more information about hannaford's doings on the evening preceding his death—granett—was dead, evidently poisoned, as hannaford was poisoned. these were circumstances—they've probably occurred to both of you—which led us to believe that hannaford had formed the acquaintance of folk here in town who were of a shady sort. and one thing was absolutely certain—if the gang, or if baseverie, had really got that warrant, they had got it from hannaford! eh?"

"that may be taken as certain," assented hetherwick. "either directly or indirectly, it must have been from him."

"we think they, or he, got it directly from him," said blenkinsop. "our theory is that if there is a gang baseverie is an active, perhaps the leading, member; that hannaford was previously acquainted with him or some other member; that hannaford was with him or them on the evening preceding his death; that he jokingly told them that he had discovered the identity of madame listorelle with mrs. whittingham; and that they poisoned him—and granett, as being present—in order to keep the secret to themselves and to blackmail madame listorelle and her sister, lady riversreade. that's our general idea—and that's why, on monday noon, we issued the advertisement. we meant to keep things to ourselves at first, and if substantial evidence came, to pass it over to the police. now you know everything. it may be, if there is a gang, that one member will turn traitor for the sake of five thousand pounds and if he can exculpate himself satisfactorily; it may be, too, that matters will develop until we're in a position to fasten things on baseverie——"

"i still wish that either lady riversreade or major penteney had handed him over to custody!" said matherfield. "you see——"

"you've got to remember that baseverie never demanded anything for himself," interrupted penteney. "he represented himself as a go-between. but our man's safe enough—a retired detective, and——"

just then a clerk opened the door and entered with a telegram. blenkinsop tore open the envelope, glanced hurriedly at the message and flung the form on his desk with an exclamation of annoyance.

"this is from our man!" he said. "sent from dover. followed baseverie down there—and baseverie's slipped him!"