The hours dragged wearily with Foyle. The soft breathing of the sleeping man as he rested with his head pillowed on his arms was the only sound that broke the stillness of the night. The superintendent himself dared not sleep. He tried to read, but the magazines failed to interest him. He got up and quietly strolled about the room, examining the bookcases with incurious interest.

His thoughts were busy. Apart from all the other facts, Grell's manner was more than sufficient confirmation of the fact that he was holding something back—something vital to the success of the investigation. The superintendent had a very shrewd idea of his reasons. Grell was a strong man—a man likely to hold to his own line at all costs. He had already proved that no personal considerations would move him.

The superintendent reviewed the situation impartially, his brow furrowed, his lips tight pressed together. He was as certain as though he held the other's signed confession that Robert Grell had it in his power to say who killed Goldenburg. How would he break through his silence? For, come what might, he felt that Grell's place was rather in the witness-box than in the dock. That he preferred the dock was proof of the strength of the motive which actuated him. No amount of persuasion, Foyle knew, would make him open his lips. Disgrace by the fear of a public trial had failed to move him. If he was to be induced to tell his secret it must be by strategy.

Heldon Foyle held his own code of ethics in his profession. In his own mind he held that all things which were legal were permissible in facilitating the ends of justice. Grell could, if he were so minded, give sworn evidence on what Foyle could only suspect. Grimly the superintendent resolved that in a contest of will he would win.

A gentle tap at the door broke his train of reflection, and the white face of the housekeeper peered in. Her eyes rested first on the sleeping man, but his attitude concealed the handcuffs. She turned a half-frightened glance on Foyle.

"Excuse me, sir. I couldn't sleep, so I dressed, and thought I would look in to see if Mr. Grell or you would like anything. Perhaps a cup of coffee——"

"No, thank you," said the superintendent. "By the way, now you're here you'll perhaps tell me whether you expected Mr. Grell's arrival. Didn't you think he was dead?"

She advanced a little into the room, closing the door behind her. "That I did, sir," she answered timorously. "I couldn't make it out when I got his telegram from Liverpool. It gave me a shock."

"From Liverpool?" repeated Foyle slowly. "So he sent a wire from Liverpool, did he? Would you mind if I had a look at it?"

He could see the hesitation in her face and went on: "See here, Mrs. Ellis, there has been a murder, though, fortunately, Mr. Grell was not the victim. I am interested in the matter, and you will be acting in his interests if you show it to me."

"I don't know what to do, I'm sure," quavered the woman irresolutely. "I was supposed to have burnt it. Hadn't I better wake him up, and then he can let you look if he likes?"

A strong hand pushed her back as she would have endeavoured to rouse Grell. "I shouldn't worry him if I were you," said Foyle. "You may take it that I have a right to see that message."

He spoke authoritatively. Her hand fumbled beneath her apron and she produced a buff-coloured envelope. The detective took out and unfolded the wire. He read—

"Mrs. Ellis, Dalehurst Grange, Dalehurst.—There has been mistake of identity. Am safe and well. Shall be down this evening, but time uncertain. Please have room ready. Let no one know you have heard from me. Burn this.—R.G."

The detective refolded the telegram and placed it in his waistcoat pocket. His mind dwelt more on the significance of its dispatch from Liverpool than on the message itself. The Princess had been at Liverpool. It was a plausible presumption that she had sent the wire and that she therefore must have been in touch with Grell.

"Yes, I guess you must have been a bit startled when you got that," he said. "Did Mr. Grell give any explanation when he came?"

"Yes, in a way. He got here an hour or two after it came and must have let himself in with his own key. He walked in on me while I was doing some sewing in my own sitting-room. He said that the police had asked him to keep out of the way, because if it was known that he was alive it might hamper them. He told me not even to let the maids know that he was here, and he came straight up to this room and locked himself in. I had made a bed ready, but he has slept on the couch over there." She nodded towards a big settee under the window. "He said the bedroom might do for a lady friend he was expecting who might arrive at any moment. He told me, too, that it might be necessary to leave suddenly."

The old lady had, it was evident, made a good guess at the identity of her questioner or she would not have answered so freely, in spite of the detective's authoritative manner. Foyle put one or two further questions to her and then dismissed her with a quiet word of thanks. He began to see that he had struck harder than he knew when he had descended on the house in the guise of a burglar. Dalehurst Grange was, of course, a rendezvous, and the Princess Petrovska was on her way to join Grell. The superintendent rubbed his hands together as he thought of the surprise in store for her.

Dawn was breaking over the woods when Robert Grell woke with a shiver. He stood up and stretched himself. "Good morning, Mr. Foyle," he said genially. "I'm afraid I dropped off, but I've had rather a wearying time lately. Now, what's the programme? I suppose a bath is out of the question, or"—with a glance at his fettered hands—"even a wash may be dangerous. Faith, you don't believe in running risks!"

Foyle smiled in response to the banter. "Only a fool runs risks when there's nothing to be gained. But I'm prepared to run one if you like to fall in with a plan I've thought out. You're not under arrest yet. You needn't be if you care to undertake to give evidence when the inquest is resumed. For you are at present the only person who can clear up the whole thing. Mind you, it would depend on what came out at the inquest whether we should then arrest you. I can give no guarantee about it. But if you accept, all that will be necessary is to quarter a couple of my men with you for the time being."

Grell walked to the window and stared out upon the wooded country. Presently he wheeled upon the superintendent with a short laugh. "My dear man," he cried, "you will harp on that one point. I appreciate your offer of comparative liberty, but if I accepted I should do so under false pretences, because my evidence will be that I know nothing."

"You can't stop my knowing the truth," answered Foyle equably. "Sooner or later I shall be able to prove it. And if you persist it will make things much more unpleasant for you."

The other said nothing for a while. A struggle was taking place in his mind that was indicated with a nervous twitching of the fingers. His shoulders were bent and his head bowed. Foyle waited patiently. Outside a bird started a "jig-jig-jig—br-brr" that set the teeth on edge. The trees, stirred by a newly sprung up breeze, rustled uneasily.

"No, it's no good," said Grell at last. "I know nothing."

The detective rubbed his chin thoughtfully. "Will you tell me if you had any visitors on the evening of the murder?" he inquired, blandly ignoring the other's refusal. He noticed a quick flash of surprise pass over Grell's countenance and drew his own conclusions. Swiftly a new thought came to him. "Did Goldenburg come to you alone?"

The prisoner remained silent, and Foyle knew that he was considering the advisability of answering. "I don't see why you shouldn't know that, if you want to. He came with a friend of mine. She left shortly afterwards."

"She?" Foyle seized on the word. "It was a woman, then?"

Grell bit his lip. He had said more than he meant to. The superintendent frowned thoughtfully, and his active brain was beginning to see things more clearly. It was a full five minutes before he spoke again as one making an assertion rather than asking a question.

"That would be Lola, of course." His blue eyes met Grell's frown with an ingenuous stare. "This is beginning to get clearer, Mr. Grell. Goldenburg was blackmailing you, eh? Maybe he had letters which you wouldn't have liked Lady Eileen to see—what?"

An ejaculation came from Grell. The detective directed his gaze to a picture opposite him, and continued, as though thinking aloud—

"Now I come to think of it, was Goldenburg a relative of yours? The likeness is amazing. Well, suppose, for the sake of argument, he was. And Lola—where does Lola stand? Was it to her, by any chance, that the letters were directed? Was she merely a friend, or did she stand in closer relationship to either of you?"

Grell yawned ostentatiously, but although Foyle had been apparently looking away from him he had followed the effect on the other's face of every one of the seemingly casual questions he had put.

"I am afraid I am boring you. It's a bad habit, thinking aloud."

"It does seem futile," agreed Grell. "You surely have little need to exercise yourself about these things."

"Ah, you think so? I am beginning to think that something more is necessary. It may be—of course, this is only for the sake of illustration—that the dagger was handled by some one after the murder had occurred. However, let the subject drop. Perhaps your housekeeper will get us some breakfast while one of the girls runs into Dalehurst."

While waiting for a reply, he rang the bell and gave some directions, with a note to the housekeeper. The breakfast that she ultimately served up was a credit to her skill as a cook. Both men ate with an appetite that the unusual nature of the situation did not destroy, though Grell found the handcuffs troublesome.

The superintendent laid down his knife with a sigh of content.

The sound of a motor-car horn was borne faintly in upon them. In a few minutes the housekeeper ushered Green and Malley into the room. The chief inspector returned Foyle's greetings and flung his heavy overcoat on to a chair. His eyes wandered over the prisoner with a little pardonable curiosity. Grell bore the inspection with a smile.

"I congratulate you, sir," said Green. "We'll have the thing fairly straightened out in a day or two now."

"I hope so," said Foyle. "Mr. Malley, will you stay with this gentleman for five minutes? I want to speak to you in another room, Green."

He led the way to the little sitting-room, through the window of which he had effected an entrance. A look of comprehension spread over Green's face as he noticed the missing diamond pane. "Malley told me he passed you in the village yesterday. You got our man quicker than I should have thought possible in the circumstances. How did he take it?"

The superintendent gave a brief recapitulation of the steps he had taken since he left London. Green rubbed his grizzled head and followed the recital with keen appreciation. It did not occur to him to feel hurt that Foyle had acted independently.

"As a matter of fact," he said, "I've got a search-warrant in my pocket, and we were coming over this house to-day. I didn't anticipate much profit, because he could have easily slipped away into the woods. I got the county constabulary to put a cordon of patrols round about, and hoped to drive him into their hands. But it was a slim chance. However, we've got him now."

"Yes, we've got him now," agreed Foyle. "There only remains the Petrovska woman, and we'll have her to-day. Listen."

He told of what he had learned from the housekeeper, and they discussed the probabilities of the woman reaching Dalehurst Grange. If she managed to escape Blake and the other detectives who were hot-foot on her trail there was little doubt but that she would walk blindly into a trap. That she had not already reached the Grange and departed Foyle was satisfied, although she had had ample time to travel from Liverpool. As Green phrased it, "she might almost have walked it." But the exigencies of the pursuit might have brought about delay if she attempted to confuse her track. If Foyle had been able to get in touch with Blake he would have called him off in order to let her proceed unfettered. That could not be done.

"She'll not dream anything's wrong here if we're careful," said Green. "Will you wait for her, or shall I?"

"This is up to you, Green. I'll leave you. You might have had Malley, but I can't drive the car myself, and I want to get back to town. Do you think you'll be able to manage alone?"

"I think so," said the chief inspector confidently.

"I'll get the local superintendent to send up a couple of plain-clothes men as we pass. You'll bring her straight back to town."

"Ay!"

In a quarter of an hour all preparations were finished. Malley was in the driving-seat of the car. Foyle and Grell sat in the tonneau, and it was no coincidence that the right hand of the prisoner and the left hand of the detective were hidden beneath the rug which covered their knees. For Foyle had handcuffed his man to himself. It was merely a matter of travelling precaution. The superintendent did not believe that Grell would attempt to escape, but there was no excuse for giving him any temptation. Anyway, it did no harm.

"You'll charge him with the murder directly you reach town, I suppose?" whispered Green, standing by the step of the car.

"Murder?" repeated Foyle. "Grell did not commit the murder. I shall detain him a day before making any charge against him at all. Drive on, Malley. See you later, Green."

The car whizzed away. Chief Inspector Green stood bare-headed in front of the house, scratching his head, and with a look of bewilderment on his face.