Foyle inclined his head. His blue eyes were alight with interest which he made no effort to conceal. He half guessed what was coming, but he found Grell's ways disconcerting and could form no certain judgment.

Certainly Grell did not behave like a guilty man--that is, a man guilty of murder. But neither did he behave like an innocent man. He was too totally unconcerned with the gravity of his position.

"Yes, there were finger-prints," he said. "I have a photograph of them in my pocket if you would like them compared now."

"With mine? That's what I was about to suggest. You'll find some writing-paper and ink in the desk behind you. I suppose they will do."

The prisoner smiled as he saw Foyle carefully shift his chair to guard against any sudden rush, before turning his back. He was a moment preparing the materials and then placed a blank sheet of paper on a little table in front of Grell. "Will you kindly hold out your hands?"

he said. As Grell did so he smeared the tips of the fingers of the right hand with ink. "Now press your fingers lightly but firmly on the paper.

Thank you."

He brought a little standard lamp closer, and under its rays studied the two sets of prints closely. He did not need a magnifying-gla.s.s to see that none of Grell's finger-marks agreed with the two that were clear on the dagger. Grell leaned back in his chair as though the matter were one of complete indifference to him.

"Does that satisfy you, Mr. Foyle?" he asked at last.

The superintendent nodded as their eyes met. "It satisfies me that you did not actually kill the man," he said steadily. "I'll own I'm not surprised at that. I believe if you had killed him you would have been man enough to have stayed and faced the consequences. You will observe that I have not formally arrested you yet. But I do believe that you know all about the crime--that you were perhaps an eye-witness."

For the first time during the interview Robert Grell lost hold of his self-control. His fists clenched and the steel of the handcuffs bit deep into his wrists as he momentarily forgot that he was handcuffed. There was a meaning in Foyle's tone that he could not fail to understand. He caught at his breath once or twice and his temples flamed scarlet.

"Speak plainly now!" he cried hoa.r.s.ely. "What are you hinting at?"

Slowly Heldon Foyle began to tear the sheet of paper bearing Grell's finger-marks into minute fragments. He was calm, inscrutable. "I thought I made myself clear," he replied. "To make it plainer I will ask you if a man, famous, rich, and with an honourable reputation, flies on the eve of his wedding-day, a.s.sisted by his valet, hides himself in a low part of London, and a.s.sociates with doubtful characters, whose friends abduct and drug police officers, who uses, in short, every effort to avoid or to hamper justice--has not some strong reason for his actions? Is it not plausible to suppose that he is an accessory either before or after the fact?"

Grell sighed as if in relief, and, stooping, picked up his cigar, which had fallen on the carpet. He had recovered his calm. "You are a better judge of evidence than I am," he said unemotionally. "Personally, I don't think the facts you have mentioned would convict me of anything but eccentricity. Who is this Harry Goldenburg, anyway? Beyond the fact that he's my double I know nothing of him. That's certainly a coincidence, but why on earth I should conceal anything I know is beyond me."

"You're talking nonsense, Mr. Grell, and you know it," said Foyle, with a weary little gesture. "There's too much to be explained away by coincidence. We know who Harry Goldenburg was, and that there was a strong motive for your wishing him out of the way." He leaned over a little table and his face was close to Grell's. "You can only delay, you cannot prevent justice by keeping your mouth shut."

The firm lines of Grell's mouth grew obstinate. "I shall stick to my story," he said. And then, with a return to his former flippancy of manner, "You're a clever man, Mr. Foyle. I never realised till you and your men were on my heels how hard a time a professional criminal must have. Even now I am not clear how you knew I was down here. When I found the police in charge of the motor-car I had left I thought they were merely guarding it as a derelict. I did not guess that you knew I had escaped from London in it."

"A mere question of organisation," said Foyle. "As a matter of fact, we know most of your movements from the time you left Sir Ralph Fairfield's flat to the moment you separated from Lady Eileen at Kingston. By the way, she made some money over to you. You may care to know that that was got by forgery."

Surprise had leapt into Grell's face as the superintendent drily recounted his movements. It was succeeded by a flash of fury at the last words. "Be careful, sir," he said tensely. "You need not lie to me."

"It is the simple truth. Lady Eileen got a note from you asking for money. She had none, and her father was out, so she signed a cheque in his name and cashed it personally."

Grell's face had become grey and he buried it in his hands. His shoulders shook and Foyle could understand how hardly he had been hit.

To have had to appeal to the girl for monetary help was bad enough. To find that she had committed a crime to help him was to add an anguish to his feelings that he had not known before. Somewhere in the house a clock struck midnight, the slow, deep strokes reverberating heavily.

"She did _that_--for me!" said Grell, lifting his head, haggard and wan.

Then, as a thought occurred to him, "She is not under arrest?"

"No. I had her word that she would inform her father."

Grell made no answer. He stared moodily in front of him. The superintendent had no desire to break in on his reverie. He walked across the room, picked up a magazine, and sat down, again facing his prisoner, while he idly turned over the pages. Presently Grell's head drooped forward.

He was asleep.

CHAPTER XLVIII

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 att.i.tude 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 ap.r.o.n 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 ident.i.ty. 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 ident.i.ty 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."