Mr Arbor was now imbued with a certain degree of calmness. But he was not at his ease. His glance had gone to the portrait of Sir William, a white eagle in the dusky room, and his discomfort seemed to grow. He had not let Hobbes take his hat or coat.

`Good evening, Inspector,' he said. `Tritely, I suppose I ought to say good morning. It… er '… I confess, Inspector, that your request to come here somewhat startled me. I…'

`Sit down there,' interrupted the doctor, leading him to the fire. `You remember my colleague here?'

`Yes. Er.. yes, of course,' Arbor said, vaguely. He added, `Is Sir William about?'

`No. That's it. Sit down.'

`I presume he has been informed of my purchase of the manuscript?' inquired Arbor.

`He has. But it doesn't matter now, you know. Neither of you will ever have it. It's burnt.'

The man's finger darted to his eyeglasses to keep them on. He said: `You mean… he… somebody… that is.' Arbor made an uncertain gesture. `How was it destroyed? This is terrible, Inspector!'

The doctor drew out his pocket-book. Carefully he took from it the only part of the manuscript which remained, and stood weighing it thoughtfully.

`May. I… may I see that, Inspector?'

He took the flimsy strip of paper in unsteady hands and held it close under the pink shaded lamp. For some time he studied it, back and front. Then he looked up. `Undoubtedly… ah.. undoubtedly. Inspector, this is an outrage, you know! I own this.'

`Is it worth anything now?'

`Well…'

`I see that there's some hope for you, then. Now, I'll tell you how it is, Arbor,' said Dr Fell, in an argumentative voice suggestive of the elder Weller. `If I were in your shoes, I should take that bit of paper, and put it in my pocket, and forget all about it for the present. You're in enough trouble as it is.'

`Trouble?' demanded Arbor, in rather too challenging a voice. The way he held the paper reminded Rampole of a man with stage-fright holding his notes on a lecture platform; calm in every way except that betraying flutter of the paper,

`Do you know,' continued the,' doctor, pleasantly, `that I've been of half a mind to let you cool off in gaol for a day or two? Why did you run away?'

`Run away? My dear man…!’

'Don't try to deceive me,' said the doctor, in a sinister voice. It was a rather less blatant resurrection of Hamlet's father's Ghost. 'Scotland Yard sees all. Shall I tell you what you did?'

He proceeded to give an account of Arbor's behaviour after leaving the Tower. It was accurate enough in its details, but so neatly distorted that it sounded like the flight of a guilty man from the law.

`You said,' he concluded, `that you had important information to give me personally. I am willing to listen. But I warn, you, man, that your position is very bad. And if you don't tell me the whole truth.

Arbor leaned back in the chair, breathing noisily. The strain of the day, the late hour, all his experiences since the murder, held him limp and nerveless.

`Ah yes,' he murmured. `Yes. I perceive, Inspector, that circumstances have put me in a false light. I will tell you everything. I had intended to do so, but now I see I have no choice. You see, I felt that I was in a doubly unfortunate and precarious position, I feared that I might not be threatened only by the police, but by some criminal as well.

I am… a man of books, Inspector. My life is sheltered. I do not mingle with the more… ah… tempestuous portions of the world. You, who are a man of rough existence, and accustomed to hand-to-hand encounters with desperate ruffians, will not understand what I felt when I was faced with a bewildering problem of criminal nature.

'It began with that cursed manuscript. I came here for the purpose, of getting it from Bitton. Not unnaturally — a querulous note raised his voice — `I wanted my own property; But I hesitated. Owing to the unpredictable eccentricities of Bitton's nature, I was placed in a distressing dilemma.. '

`I see,' said Dr Fell. `What you, mean is that you were afraid of Bitton, and so you had to hire somebody to pinch it for you.'

`No!' Arbor insisted, gripping the arms of the chair in his earnestness. `That is precisely what I do not mean. I feared you would think so, as your colleague indicated this afternoon. And I was careful to point' out to all of you there could have been no legal steps taken against me had I done so… But, Inspector, I did not do it. I will take my oath on it.

'When the manuscript was stolen it was as much of a surprise to me as it was to Bitton. The first I heard of the theft, you see, was when he telephoned to my friends, the Spenglers, on Sunday night to… ah… to see where I was. But then…'

He caught Dr Fell's cold eye, and there was a new vehemence in his tone.

`Then, considerably later the same night, I received another phone call at the Spenglers'.'

'Ah!' grunted the doctor. `From whom?'

`The person refused to give his name. But I was almost positive I knew whose voice it was. I thought it was the voice of young Mr Driscoll.'

Dr Fell jumped. He glared at Arbor, who returned his gaze with a dogged steadiness. Arbor went on:

`I reviewed everything in my mind, and I was sure. I had met this young man at dinner the week before, when I had made almost reckless remarks and exceedingly broad hints about the Poe manuscript. The only other persons who could have heard them were Miss Bitton and Sir William; they were the only others at the table… Hence I was sure when this voice spoke. He asked me whether I was interested in a Poe manuscript belonging to Sir William Bitton, and gave such details of what I remembered having said, that I had no doubt. He asked me what price I should be willing to pay, no questions asked, if the manuscript were handed over to me.

`I am ah. accustomed to rapid decisions and prompt action, Inspector. I was, sure I; was dealing, with a member of the family. The voice, it is true, was somewhat gruff; but I had little difficulty in seeing through, the disguise. Dealing with a member of the family was very different from dealing with a hired burglar. In case of trouble, there would be no scandal. In any case, there could be no prosecution against me.. This person naturally did not know I was the owner of the manuscript; nobody did. If, therefore, he had any ideas of blackmail in his mind after the theft, I could afford to smile. He would be the only one to take the risk.

`I reviewed my position in a moment, Inspector, and I perceived that this was… ah… the easiest solution of, my difficulties. After the manuscript came to my hands, I could always drop a note to Sir William explaining my ownership, and referring him to my solicitors in case he did not believe me and wished to prosecute. I knew he would not do so. Besides, it was… ah… obvious,' said Arbor, hesitantly, `that the amount of the commission… ah…'

`You could promise him whatever he asked,' said the doctor, bluntly. `And when you got the manuscript you could give him fifty pounds and tell him to whistle for the rest because you owned it and he was the only thief. And the fifty pounds would be much less than you'd have to pay Bitton.'

`Considerably less. You state matters very succinctly, Inspector,' Arbor nodded. `I agreed to what the unknown person said, and asked him whether he had the manuscript. He replied that he had, and again demanded how much I should pay for it. I mentioned rather a large sum. He agreed, and stated that he would name a rendezvous in the course of the next day. I was to be communicated with through the Spenglers. His stipulation was that I must never inquire into his identity.'

`Well?' prompted the doctor.

`Naturally I attempted to trace the call, when he had hung up. It was impossible.' `Go on.'

Arbor glanced over his shoulder. The nervousness had come back again.

`The following day, today, I went about my affairs as usual. I paid a long-delayed visit to the Tower of London; And, I proceeded exactly as I have told you. When I was detained on my attempt to leave by the news of the murder, I was not unduly upset. I thought, indeed, that it would be, fascinating to watch Scotland Yard at work, and I assumed that it was some member of the underworld who had been killed.'

Again Arbor adjusted his glasses. `You will own, Inspector, that it came as a shock when you began your questioning of me by inquiring about Poe manuscripts. Even so, I flatter myself, that I was cool and… you will pardon me… triumphant over you. It was not until you mentioned the name of the dead man that He drew out the silk handkerchief and mopped his forehead. `My heart, Inspector; I could not see it would make me betray weakness. The possibilities had suddenly become menacing and horrible. Driscoll, at my order, had promised to deliver me that manuscript; and now he was murdered. I must assume even now that he was killed because of it. It occurred to me that in some heinous fashion, I might come into the case as accessory of some sort. A murder case.' He shuddered. `I could not see how it might concern me directly, but there were any number of dangers. And where was the manuscript? You had not found it on Driscoll's body. I wanted to forget it. As you saw, I wanted no search for it, above all things, because a search might uncover evidence to lead to me.'

`So far,' said the doctor, `very well. What then?'

Rampole was puzzled. If the doctor had insisted on anything in the case so far, he had insisted Driscoll would never attempt to dispose of the manuscript to Arbor. But here he was, nodding ponderously and fixing his sharp little eyes on the collector as though he believed every word. And Rampole, too, was compelled to believe Arbor. There was only the possible explanation that Driscoll, in a moment of panic, had made to Arbor an offer whose dangers he saw in a calmer moment the next day, and decided to drop the whole affair….

`Now,' said Arbor, clearing his throat now, Inspector, I come to the amazing, the incredible part of my whole story.. If you could have imagined'…!’

'Just after you left us in the Warders' Hall,' the doctor interposed, slowly, 'you got the fright of your life, and it sent you out to Golders Green in a, blind panic. What was it?

Arbor seemed to have come to a jumping-off place in his narrative; he hesitated on the brink of the leap, tapping his glasses and peering over.

`Inspector,' he said, `before I tell you what you must regard as completely incredible, let; me ask you a question' or two. In that room when you were questioning me, who was present?'

`H'm. There was Hadley, my my colleague; and Mr Rampole here; and General Mason, and Sir Wil — Hold on, no! I'm wrong. Bitton wasn't there. He had gone up to Mason's rooms.'

Arbor stared. `Bitton was at the Tower?'

`Yes.. But he wasn't in the room with us. Proceed.'

`The next thing,' Arbor said, carefully, `is… ah, what shall I say?… an impression, rather than a question. Speaking with someone on the telephone is, in a certain sense, somewhat like speaking to a person in the dark. You hear the voice alone. There is no personality or physical appearance to distract you from your impressions,' of the voice itself. If you heard a voice on the telephone, without having seen the speaker, and later you meet the speaker in real life, you might not recognize him, because his appearance or his personality might destroy the impressions of the voice. But if you heard him in the dark… '

`I think I understand.'

`Very well. You dismissed me after the questioning, you will recall, and I went outside. The door of the room in which you had been talking to me was not quite closed. It was very dark and quite misty under the arch of the Tower there. I stood outside the door to accustom my eyes to the gloom. As it was, I was terrified. I could with difficulty make a good exit from the room. There was a; warder on duty, but he stood at some distance from me. I could hear you talking in the room I had left….

`Then Inspector,' said Arbor, bending forward with fist clenched, `I think I received the most horrible shock of my life. In the room I had not noticed it, I suppose, because the influence of personalities had overborne the impressions of my hearing.

`As I stood there in the dark, I heard a voice speak from the room. It sounded little louder than a whisper or a mumble. But I knew that the voice I heard from that room was the same voice which had spoken to me on the telephone the day before, and offered to sell me the Poe manuscript.'