"Very well; I am content with that." The prisoner nursed his chin in his cupped hands and stared unseeingly at the distempered walls. "It began years ago, on a little farm in New Hampshire. That was my father's place. He died when I was six or seven, and my mother married again. The man was the father of Harry Goldenburg. I was eight years old when Harry was born. Four years later, my mother died, and when I was sixteen I ran away from home. You will know something of my career since then: the newspapers have repeated it often enough—office-boy, journalist, traveller, stockbroker, politician. I was still young when I became a fairly well-known man. In the meantime I had not seen nor heard anything of my brother except that he had left the village when my stepfather died.

"In Vienna some years ago I became intimate with Lola Rachael—the woman you know as the Princess Petrovska. She was a dancer then and had hosts of admirers among the young men about town. As a matter of plain fact, I believe she was employed by the Russian Government for its own purposes. But of that I was never certain. Anyway she entangled me. And I believe she really had an affection for me. It was during that time that I was fool enough to write her letters—letters which she kept.

"Eventually I went back to the United States. I became a state senator and became involved in politics. One day I was in my hotel in Washington when I received a visit from my brother Harry Goldenburg. I was in a way glad to see him, although he was practically a stranger. He impressed me favourably—perhaps the fact that we were so alike physically had as much to do with it as his suave ways and gentle manners. Even at the time I believe he was suspected by the police of being an astute swindler. Of that, of course, I was ignorant. He told me a story of a mail order business he had established in Chicago which was doing great things, but which was hampered for lack of capital. Well, to cut the story short, I lent him five thousand dollars. A month later, he wrote to me for two thousand, and got it. A few weeks after that I read of a great fraud engineered in Central America and there was a three-column portrait in the paper of the man at the bottom of it—my brother. That opened my eyes. When next he came to me—he was audacious enough to do it within the year—I charged him with living by fraud. He laughed in my face and admitted it. When I threatened to call in the police, he merely shrugged his shoulders and asked what I thought of a flaming headline in the press:

'BROTHER OF SENATOR GRELL HELD FOR BIG FRAUDS.'

"I could see it all just as he painted it. My political career was very dear to me just then. Such a thing would have killed it. I knew if I exposed him he was capable of carrying out his threat. However, I told him to get out of the place before I threw him out of the window. He could see I was losing my temper and took a little pistol from his pocket—a Derringer.

"'I have a number of letters which you sent to a lady in Vienna,' he said. 'I know many newspapers which would offer me a good price for 'em.'

"I think it was perhaps fortunate for me that he held the pistol—or I might have done something I should afterwards have regretted. He flung a letter face upwards on the table. It was one of those I had written to Lola Rachael. If he had the rest of the correspondence—and he swore that he had—it would have been deadly in the hands of an unscrupulous political opponent. As you know, electioneering in the States is rather different from what it is here. I was fool enough to pay him money on his promise to suppress them. He would not sell them outright.

"That was the beginning. After that I never had a secure moment unless I was away on an exploring expedition. The moment I reappeared in civilisation my brother would seek me out. He was cunning enough to press me only to the verge of endurance. He could judge exactly how much I would stand. At last, however, I resolved not to yield another penny to his extortions. I cut loose from all my affairs in the United States and came to England. I thought I could fight him when I had reduced the stakes. I found after all that I had increased them, for I met Eileen—Lady Eileen Meredith."

He paused. Neither of his two hearers said anything. An injudicious remark might break the thread of his thoughts.

"When I became engaged to her," Grell resumed, "I knew that it would not be long before Goldenburg would see his chance. I set to work to find Lola, and discovered her as the Princess Petrovska. Then for the first time I learned that she had married Goldenburg—but she admitted that any affection she held for him had long since faded. They had parted a few weeks after the marriage—which they both seemed to regard somewhat cynically—and she had resumed her first husband's name. She admitted that she had helped him to blackmail me, but apparently she herself had handled little enough of the loot. She was vicious enough about it. I gave her a cheque and induced her to come to London. I had it in mind to stop this blackmail before I was married.

"As I expected, Goldenburg was not long in scenting profit. He descended on me ravenously. I told him that I would pay him ten thousand pounds if he would put all the letters he possessed in my hands but that I would not otherwise buy his silence. He could see that I was in earnest, and asked for time to consider. I gave him till the night before my wedding. I said nothing of the Princess Petrovska. I knew that they would meet. One cannot be too scrupulous in dealing with a scoundrel, and she had her instructions—to steal the letters from him if necessary, while pretending that she was only anxious to join forces with him in looting me.

"But all her efforts went for nothing. He recognised the value of her co-operation in the circumstances, but would give her no hint of the place where he had concealed the letters. Time drew on. You will know enough of her to recognise Lola as a clever, resolute woman. She made up her mind to accompany Goldenburg to his appointment with me as a last resort. It was to keep that appointment that I left Ralph Fairfield at the club the night before the wedding—the night of the murder."

He breathed heavily. Thornton picked up a piece of paper and crumbled it nervously between his lean hands. Foyle, eager and alert, was leaning forward, anxious not to miss a word. A great deal of what had been obscure was being cleared up. But so far nothing that Grell had said but could be interpreted as a motive—and a singularly strong one—which might in other circumstances weave a hangman's rope about his own neck.

"You did not want any one to know that you were absent from the club," remarked Foyle. "Why?"

"That was merely a matter of precaution. I wanted my interview with Goldenburg to be secret. I had given Goldenburg a note which would ensure his being shown to my study and I was purposely a bit late for the appointment. I wanted to give the Princess Petrovska all the opportunities possible. But when I reached there it was clear to me that she had failed. He had not brought the letters with him. I got rid of the woman, and Goldenburg and I quarreled. Then it was that I killed him."

"And what of the other woman?" asked the superintendent.

"What other woman?"

"The veiled woman who was shown up to you by Ivan."

"There was no other woman," said Grell, his lips tightening. "I have told you as much as I intend to."

"Just as you like. I believe you have told the truth up to a point, Mr. Grell. It is fair to assume that a blackmailer of Goldenburg's calibre would have taken precautions lest you should fail to comply with his demands. Doesn't it appear a fair assumption that he might have taken steps to arrange the presence of the person most interested, next to yourself? He probably never mentioned that he had done so until it was too late for you to stop her. I mean Lady Eileen Meredith."

The table crashed to the floor as Grell, the last remnants of his self-restraint gone, leapt to his feet. Sir Hilary Thornton sprang between the two men. Foyle also had risen, and though his face was impassive the blue eyes were sparkling and his fists were clenched.

"You liar!" raved Grell. "How dare you bring her name into it!"

"This excitement will not advance matters," said Foyle placidly. "Sit down for a little, Mr. Grell. You cannot prevent the inevitable."

The tense muscles of the prisoner relaxed and a shivering fit shook him from head to foot. He could see the blow that he had striven to avert falling while he stood impotent. He had taken every risk, made every sacrifice man could make, to turn it aside. Now he had been told that he had failed. It was not easy to admit defeat. His debonair courage had gone.

Sir Hilary Thornton laid a hand gently on his shoulder. "My dear Mr. Grell," he said, "I don't want to use the ordinary cant about duty and all the rest of it. We may sympathise with you—personally, I admire the attitude you have taken, though perhaps I shouldn't say it—but our own feelings do not matter the toss of a button. Nothing you can do or say will swerve us from what we judge to be the interests of justice."

"Let me alone for a little while," answered Grell dully; "I want to think."

They sent him back to the detention-room where, with a constable seated opposite to him, he was to spend the night. Foyle rested one arm on the mantelpiece and kicked the fire viciously into a blaze.

"Ours is an ungrateful business, Sir Hilary," he grumbled, "but I've never come across a man who put so many difficulties in the way of being saved from the gallows as Mr. Robert Grell."

Thornton took a long breath that was almost a sigh. "Poor chap," he said reflectively. "Poor chap!" And then, after an interval, "Poor girl! Couldn't you have dropped a hint, Foyle?"

The introduction of sentiment into business was a folly that Heldon Foyle seldom permitted himself. With a shrug he pulled himself together. He shook his head. "We've got to be more certain yet. I daren't tell him too much—for my idea may prove to be wrong. You must remember that it was undoubtedly Eileen Meredith's finger-prints on the dagger. At present it is only surmise of mine how they got there. Finding the prints on her blotting-pad, which I showed you, corresponded with those on the dagger you gave me, was one of the biggest surprises of my life. But we may clear it up now."

"H'm," said Thornton. "Well, we shall have to look sharp."

A thought struck Foyle. He stood rigid as a statue for a moment, and then slapped his knee with sudden energy, "By God! I believe I've got it!" he exclaimed, and jumped for the telephone.

"Put me through to the Yard.... Hello! I want Mr. Grant.... That you, Grant?... About the Grosvenor Gardens case. Tell me. Might the finger-prints on the dagger have been caused by some one withdrawing it and replacing it after the murder had been committed? Would the second handling have obliterated first prints?... Blurred them. I see. But if the person who first handled the dagger wore gloves? Thanks. That's what I wanted to know."

He replaced the receiver and turned triumphantly on Thornton. "That bears out my idea, Sir Hilary. Will you excuse me while I see if Bolt's on the premises?"

Without waiting for a reply, he darted from the room. The Assistant Commissioner's brow puckered and he thoughtfully replaced the upset furniture. By the time he had finished Foyle had returned.

"Just caught him," he said. "I've sent him to collect all the men he can find to make some fresh inquiries."

"I'm a little bewildered," confessed Thornton, jingling some money in his trousers pockets and turning blankly upon the superintendent. "Do you think you'll be able to do it—to bring this crime home to the Princess Petrovska?"

"I think I can," replied the superintendent. "I was a blind ass not to see it earlier. Lola's alibi—which is proved to be false, if what Grell and Abramovitch say is true—helped to blind me. I was thrown off, too, by the finger-prints on the blotting-pad, which corresponded to those on the dagger, and also to those on the typewritten warning which Ivan sent me. The only plausible motive for Grell's actions, if he was not guilty himself—and that we are fairly certain of—was his desire to shield some one else. There could be only one person for whom he was willing to make such a sacrifice—Lady Eileen Meredith."

"Yes, I understand that. But the finger-prints on the warning?"

"They puzzled me for a while. But that was made clear when I talked to Ivan. He had typed it on the blank half-sheet of a letter given to him by Grell. That letter—it is only an assumption of mine—was one that had been written to Grell by Lady Eileen. That clears that point."

"Still, I don't see how you have anything against Lola more than you had before."

"There is this. The weak link in the chain of evidence against Lady Eileen Meredith was the lack of motive. That was why I did not have her arrested immediately I found that it was her finger-prints upon the dagger. The strongest point against the Princess is the motive. She was married to Goldenburg, but was not on the best of terms with him. She was bought by Grell to play the part of Delilah to the blackmailer. My theory is this—bear in mind that it is only a theory at the moment. Grell, for some reason, left her alone with Goldenburg in his study. There was a quarrel, and she stabbed him. It must have been all over in a few seconds, and there was no outcry. You will remember that the body was found on a couch in a recess, and you may have noted that curtains could be drawn across to shield it from the rest of the room. Petrovska may have drawn the curtains and slipped away before Grell returned. She is a woman of nerve and would at once set about manufacturing an alibi."

"All this is very ingenious, Foyle," remarked Thornton, "but I don't know that it sounds altogether convincing to me."

"It is pure surmise, Sir Hilary. Its chief merit is that it fits the facts. Of course, Lady Eileen may be the murderess after all. I am only working out an alternative. To carry it on a bit further. When Lady Eileen came, Ivan showed her up to the room. No one answered his knock. She went in and shut the door after her. It is my idea that there was no one in there when she discovered the dead man. She was dumbfounded at first, and probably the body being in the shade did not permit her to see the face clearly. She placed her hand on the hilt of the dagger, intending to withdraw it, but could not bring herself to use the necessary force."

"Why didn't she call out?" demanded Thornton. "It seems to me——"

"There is no accounting for actions arising out of sudden emotions. Lady Eileen Meredith is as extraordinary a woman in her way as the Princess Petrovska in hers. She had found a man murdered in her lover's study—and she may have had a shrewd idea of the reason why she was summoned there. You follow me? Probably as she stood there, hesitating what to do, Grell returned. I think it likely that he stood by the door, took in the situation quietly, and stole away with the impression that she had killed Goldenburg. If she was bending over the dead man, that was what he might naturally think.

"It is likely that he would make up his mind in an instant. To him the fact that she had raised no outcry would be significant of her guilt. She, let us suppose, stole away, having made no attempt to examine the body closely and not daring to summon any one, for fear that Grell should prove to be the murderer. He watched her go, already determined to destroy the scent by taking the blame on his own shoulders.

"By the time she reached her own home reflection had shown her that there was one possible chance that Grell might not be guilty. She rang up the St. Jermyn's Club and asked for him. Fairfield answered, declaring that his friend was in the club, but busy—too busy to talk to the girl he was to marry next day, mark you. It is idle to suppose that she did not appreciate the excuse as a flimsy one—one manufactured perhaps for the purpose of an alibi. She must have gone to bed filled with foreboding.

"All this is hypothesis. I am supposing that she never closely inspected the features of the dead man. The next morning she is informed that Grell was the victim. At once the lie that Fairfield told her assumed a new aspect. She denounced him as the murderer. She dared not say that she was the first to discover the body, for that would have meant revealing that she knew he was being blackmailed.

"Then the Princess Petrovska paid her a visit and told her that Grell was not dead but in hiding. There was nothing for it, in default of any explanation, but to revert to the thought that he was the murderer. She went to extreme lengths to help him—even to forgery. She believes him guilty still; he believes her guilty."

"But Petrovska?" objected Thornton.

"I was coming to that. She is a clever woman. When Grell got in touch with her the following day she may have had many reasons for assisting him. She most likely had a shrewd idea of the situation and resolved to profit by it to avert suspicion. While Grell was suspected she would be safe. But it may have occurred to her that if we laid our hands on him and he told us anything, we might get on her track. Suppose that to be so, it is not difficult to see why she should take a prominent part in assisting him. She would still have a certain amount of money, for he paid her to come to England, and she, as we know, would stand at nothing."

"It all sounds very interesting," commented the Assistant Commissioner, "but it looks to me as though it may be a tough proposition to get evidence bearing it out."

Foyle pulled out his watch. "My idea may all tumble to pieces as soon as a test is applied. I can't pretend to be infallible. But we can try. I am going back to Scotland Yard now, sir. It is ten o'clock. I expect to be at it all night. Are you coming back?"

"No, I don't think I can be of any assistance to you. I shall be glad if your theory does come out all right this time. The alternative suspicions are horrible. Good night, Mr. Foyle."