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 trac............