'You'd never hear of it ordinarily,' grunted Dr Fell. ' It's one of those streets hidden behind streets, that you only stumble on by accident when you're looking for a short cut, and you're startled to find a whole community lost in the middle of London ... Anyway, Cagliostro Street is not more than three minutes' walk from Grimaud's house. It's a little cul - de - sac behind Guilford Street, on the other side of Russell Square. So far as I remember, it has a lot of tradesmen's shops overflowing from Lamb's Conduit Street, and the rest lodging - houses. Brother Henri left Grimaud's place after the shooting, walked over there, hung about for a little time, and then completed his work.'

Rampole ran his eye down the story: 'The body of the man found murdered last night in Cagliostro street, WC1, has been identified as that of Pierre Fley, a French conjurer and illusionist. Although he had been performing for some months at a music - hall in Commercial Road, E, he took lodgings two weeks ago in Cagliostro Street. About half - past ten last night, he was found shot to death under circ.u.mstances which seem to indicate that a magician was murdered by magic. Nothing was seen and no trace left - three witnesses testify - although they all distinctly heard a voice say, ' The second bullet is for you.'

Cagliostro Street is two hundred yards long, and ends in a blank brick wall. There are a few shops at the beginning of the street, closed at that time, although a few night lights were burning, and the pavements were swept in front of them. But, beginning some twenty yards on, there was unbroken snow on the pavement and the street.

Mr Jesse Short and Mr R. G. Blackwin, Birmingham visitors to London, were on their way to visit a friend with lodgings near the end of the street. They were walking on the right - hand pavement, and had their backs to the mouth of the street. Mr Blackwin, who was turning round to make sure of the numbers on the doors, noticed a man walking some distance behind them. This man was walking slowly and rather nervously, looking round him as though he expected to see someone near. He was walking in the middle of the street. But the light was dim, and aside from seeing that he was tall and wore a slouch - hat, neither Mr Short nor Mr Blackwin noticed anything else. At the same time, P.C. Henry Withers - whose beat was along Lamb's Conduit Street - reached the entrance to Cagliostro Street. He saw the man walking in the snow, but glanced back again without noticing him. And in the s.p.a.ce of three or four seconds the thing happened.

Mr Short and Mr Blackwin heard behind them a cry that was nearer a scream. They then heard some one distinctly say the words, 'The second bullet is for you,' and a laugh followed by a m.u.f.fled pistol - shot. As they whirled round, the man behind staggered, screamed again, and pitched forward on his face.

The street, they could see, was absolutely empty from end to end. Moreover, the man was walking in the middle of it, and both state that there were no footprints in the snow but his own. This is confirmed by P.C. Withers, who came running from the mouth of the street. In the light from a jeweller's window, they could see the victim lying face downward, his arms spread out, and blood jetting from a bullet - hole under his left shoulder blade. The weapon - a long - barrelled .38 Colt revolver, of a pattern thirty years out of date - had been thrown away some ten feet behind.

Despite the words they had all heard, and the gun lying at some distance, the witnesses thought because of the empty street that he must have shot himself. They saw that the man was still breathing, and carried him to the office of Dr M. R. Jenkins near the end of the street, while the constable made certain there were no footprints anywhere. The victim, however, died, without speaking, not long afterwards.

Then occurred the most startling disclosure. The man's overcoat round the wound was burnt and singed black, showing that the weapon must have been pressed against his back or held only a few inches away. But Dr Jenkins gave it as his opinion - later confirmed by the police - that suicide was not possible. No man, he stated, could have held any pistol in such a way as to shoot himself through the back at that angle, and more especially with the long - barrelled weapon which was used. It was murder, but an incredible murder. If the man had been shot from some distance away, from a window or door, the absence of a murderer and even the absence of footprints would mean nothing. But he was shot by some one who stood beside him, spoke to him, and vanished.

No papers or marks of identification could be found in the man's clothes, and n.o.body seemed to know him. After some delay he was sent to the mortuary - '

'But what about the officer Hadley sent round to pick him up?' Rampole asked. 'Couldn't he identify the man?'

'He did identify him, later,' growled Dr Fell. 'But the whole hullabaloo was over by the time he got there. He ran into the policeman, Hadley says, when Withers was still making inquiries from door to door. Then he put two and two together. Meantime the man Hadley had sent to the music - hall also in quest of Fley had phoned through that Fley wasn't there. Fley had coolly told the theatre manager he had no intention of doing his turn that night, and walked out with some sort of cryptic remark ... Well, to identify the body at the mortuary they got hold of Fley's landlord in Cagliostro Street. And to make sure it was the same person, they asked for somebody from the music - hall to come along. An Irishman with an Italian name, who was also on the bill but couldn't do his turn that night because of some sort of injury, volunteered. Harrumph, yes. It was Fley, and he's dead, and we're in a h.e.l.l of a mess. Bah!'

'And this story,' cried Rampole, 'is actually true?' He was answered by Hadley, whose ring at the bell was belligerent. Hadley stamped in, carrying his brief - case like a tomahawk, and released some of his grievances before he would even touch bacon and eggs.

'It's true, right enough,' he said, grimly, stamping his heels before the fire. 'I let the papers splash it out so we could broadcast an appeal for information from anybody who knew Pierre Fley or his - brother Henri. By G.o.d! Fell, I'm losing my mind! That d.a.m.ned nickname of yours sticks in my head, and I can't get rid of it. I find myself referring to brother Henri as though I knew that was his real name. I find myself getting imaginary pictures of brother Henri. At least we soon ought to know what his real name is. I've cabled to Bucarest. Brother Henri! Brother Henri! We've picked up his trail again, and lost it again. Bro -'

'For Lord's sake go easy!' urged Dr Fell, puffing uneasily. 'Don't rave; it's bad enough now. I suppose you've been at it nearly all night? And got some more information? H'mf, yes. Now sit down and console the inner man. Then we can approach in - humph - a philosophic spirit, hey?'

Hadley said he wanted nothing to eat. But, after he had finished two helpings, drunk several cups of coffee, and lighted a cigar, he mellowed into a more normal mood.

'Now, then! Let's begin,' he said, squaring himself determinedly as he took papers from the brief - case, 'by checking over this newspaper account point by point - as well as what it doesn't say. Hum! First as to these chaps Blackwin and Short. They're reliable; besides it's certain neither of them is brother Henri. We wired Birmingham, and found they've been well known in their district all their lives. They're prosperous, sound people who wouldn't go off the handle as witnesses in a thing like this. The constable, Withers, is a thoroughly reliable man; in fact he's painstaking to the extent of a vice. If those people say they didn't see anybody, they may have been deceived, but at least they were telling the truth as they knew it.'

'Deceived - how?'

'I don't know,' growled Hadley, drawing a deep breath and shaking his head grimly, 'except that they must have been. I had a brief look at the street, although I didn't go through Fley's room. It's no Piccadilly Circus for illumination, but at least it's not dark enough for any man in his five wits to be mistaken about what he saw. Shadows - I don't know! As to footprints, if Withers swears there weren't any, I'll take his word for it. And there we are.'

Dr Fell only grunted, and Hadley went on: 'Now, about that weapon. Fley was shot with a bullet from that Colt .38, and so was Grimaud. There were two exploded cartridge - cases in the magazine, only two bullets, and bro - and the murderer scored with each. The modern revolver, you see, ejects its sh.e.l.ls like an automatic; but this gun is so old that we haven't a ghost of a chance of being able to trace it. It's in good working order, it fires modern steel - jacket ammunition, but somebody has kept it hidden away for years.'

'He didn't forget anything, Henri didn't. Well. Did you trace Frey's movements?'

'Yes. He was going to call on Henri.'

Dr Fell's eyes snapped open. 'Eh? Look here, you mean you've got a lead about - '

'It's the only lead we have got. And,' said Hadley, with bitter satisfaction, 'if it doesn't produce results within a couple of hours I'll eat that brief - case. You remember I told you over the phone that Fley had refused to perform and walked out of the theatre last night? Yes. My plain - clothes officer got the story both from the theatre - manager, fellow named Isaacstein, and from an acrobat named O'Rourke, who was friendlier with Fley than anybody else and identified the body later.

'Sat.u.r.day, naturally, is the big night down Limehouse way. The theatre runs continuous variety from one in the afternoon until eleven at night. Business was booming in the evening, and Frey's first night turn was to begin at eight - fifteen. About five minutes before then, O'Rourke - who had broken his wrist and couldn't go on that night - sneaked down into the cellar for a smoke. They have a coal furnace for hot - water pipes there.'

Hadley unfolded a closely written sheet. 'Here is what O'Rourke said, just as Somers took it down and O'Rourke later initialled.

'The minute I got through the asbestos door and downstairs, I heard a noise like somebody smashing up kindling - wood. Then I did get a jump. The furnace door was open, and there was old Loony with a hatchet in his hand, busting h.e.l.l out of the few properties he owned and shoving them all in the fire. I said, "For cat's sake. Loony, what are you doing?" He said, in that queer way of his, "I am destroying my equipment, Signor Pagliacci." (I use the name of Pagliacci the Great, you understand, but then he always talked like that, so help me!) Well, he said, "My work is finished; I shall not need them any longer" - and, zingo! in went his faked ropes and the hollow bamboo rods for his cabinet. I said, "Loony, great G.o.ddelmighty, pull yourself together." I said, "You go on in a few minutes, and you're not even dressed." He said: "Didn't I tell you? I am going to see my brother. He will do something that will settle an old affair for both of us."

"Well, he walked over to the stairs and then turned around sharp. Loony's got a face like a white horse. Lord pity me for saying it, and he had a queer creepy look with the fire from the furnace shining on him. He said, "In case anything happens to me after he has done the business, you will find my brother in the same street where I myself live. That is not where he really resides, but he has taken a room there." Just then down comes old Isaacstein, looking for him. He couldn't believe his ears when he heard Loony refuse to go on. There was a row. Isaacstein bawled, "You know what'll happen if you don't go on?" And Loony says, as pleasant as a three - card man, "Yes, I know what will happen." Then he lifts his hat very courteously, and says, "Good night, gentlemen. I am going back to my grave." And up the stairs this lunatic walks without another word.'

Hadley folded up the sheet and replaced it in his brief - case.

'Yes, he was a good showman,' said Dr Fell, struggling to light his pipe. 'It seems a pity brother Henri had to - what then?'

'Now, it may or may not mean anything to track Henri down in Cagliostro Street, but we're sure to get his temporary hideout,' Hadley went on. 'The question occurred to me, where was Fley going when he was shot? Where was he walking to? Not to his own room. He lived at number 2B, at the beginning of the street, and he was going in the other direction. When he was shot he was a little over half - way down, between number 18 on his right and number 21 on his left - but in the middle of the street, of course. That's a good trail, and I've sent Somers out on it. He's to turn out every house past the middle, looking for any new or suspicious or otherwise noticeable lodger. Landladies being what they are, we shall probably get dozens, but that doesn't matter.'

Dr Fell, who was slouched as far down in the big chair as the bulk of his weight would allow, ruffled his hair. 'Yes, but I shouldn't concentrate too much on any end of the street. Rip 'em all up, say I. You see, suppose Fley was running from somebody, trying to get away from somebody, when he was shot?'

'Running away into a blind alley?'

'It's wrong! I tell you it's all wrong!' roared the doctor, hoisting himself up in the chair. 'Not merely because I can't see anywhere a c.h.i.n.k or glimmer of reason (which I freely admit), but because the simplicity of the thing is so maddening. It's no matter of hocus - pocus within four walls. There's a street. There's a man walking along it in the snow. Scream, whispered words, bang! Witnesses turn, and murderer gone. Where? Did the pistol come flying through the air like a thrown knife, explode against Fley's back, and spin away?'

'Rubbish!'

'I know it's rubbish. But I still ask the question,' nodded Dr Fell. He let his eye - gla.s.ses drop and pressed his hands over his eyes. ' I say, how does this new development affect the Russell Square group? I mean, considering that everybody is officially under suspicion, can't we eliminate a few of those? Even if they were telling us lies at Grimaud's house, they still weren't out hurling Colt revolvers in the middle of Cagliostro Street.'

The superintendent's face was ugly with sarcasm. 'Now there's another bit of luck for us, kindly notice. I forgot that! We could eliminate one or two - if the Cagliostro Street business had occurred a little later, or even a little earlier. It didn't. Fley was shot at just ten - twenty - five. In other words, about fifteen minutes after Grimaud. Brother Henri took no chances. He antic.i.p.ated exactly what we would do: send out a man to pick up Fley as soon as the alarm was given. Only brother Henri (or somebody) antic.i.p.ated us in both ways. He was there with his little vanishing - trick.'

'"Or somebody?"' repeated Dr Fell. 'Your mental processes are interesting. Why "or somebody"?'

'That's what I'm getting at - the unfortunate, un.o.bserved fifteen minutes just after Grimaud's murder. I'm learning new wrinkles in crime, Fell. If you want to commit a couple of shrewd murders, don't commit one and then hang about waiting for the dramatic moment to pull off the other. Hit once - and then hit again instantly, while the watchers are still so muddled by the first that n.o.body, including the police, can definitely remember who was where at a given time. Can we?'

'Now, now,' growled Dr Fell, to conceal the fact that he couldn't. 'It ought to be easy to work out a time - table. Let's see. We arrived at Grimaud's - when?'

Hadley was jotting on a slip of paper. 'Just as Mangan jumped out the window, which couldn't have been more than two minutes after the shot. Say ten - twelve. We ran upstairs, found the door locked, got the pliers, and opened the door. Say three minutes more.'

'Isn't that allowing a small margin of time?' Rampole interposed. 'It seemed to me we were doing a good deal of tearing around.'

'People often think so. In fact,' said Hadley, ' I thought so myself until I handled that Kynaston knifing case (remember, Fell?), where a d.a.m.ned clever killer depended for his alibi on the tendency of witnesses always to overestimate lime. That's because we think in minutes rather than seconds. Try it yourself. Put a watch on the table, shut your eyes, and look again when you think a minute is up. You'll probably look thirty seconds too soon. No, say three minutes here!' He scowled. 'Mangan phoned, and the ambulance was round very quickly. Did you notice the address of that nursing - home, Fell?'

'No. I leave these sordid details to you,' said Dr Fell, with dignity. 'Somebody said it was just round the corner, I remember. Humph. Ha.'

'In Guilford Street, next to the Children's Hospital. In fact,' said Hadley, 'backed up against Cagliostro Street so closely that the back gardens must be in line ... Well, say five minutes to get the ambulance to Russell Square. That's ten - twenty. And what about the next five minutes, the time just before the second murder, and the equally important five or ten or fifteen minutes afterwards? Rosette Grimaud, alone, rode over in the ambulance with her father, and didn't return for some time. Mangan, alone, was downstairs doing some telephoning for me, and didn't come upstairs until Rosette returned. I don't seriously consider either of 'em, but take it all for the sake of argument. Drayman? n.o.body saw Drayman all this time and for a long while afterwards. As to Mills and the Dumont woman - h'm. Well, yes; I'm afraid it does clear them. Mills was talking to us all the earlier part of the time, until at least ten - thirty anyhow, and Madame Dumont joined him very shortly; they both stayed with us for a while. That tears it.'

Dr Fell chuckled. 'In fact,' he said, reflectively, 'we know exactly what we did before, no more and no less. The only people it clears are the ones we were sure were innocent, and who had to be telling the truth if we made any sanity of the story. Hadley, it's the cussedness of things in general which makes me raise my hat. By the way, did you get anything last night out of searching Drayman's room? And what about that blood?'

'Oh, it's human blood, right enough, but there was nothing in Drayman's room that gave a clue to it - or to anything else. There were several of those pasteboard masks, yes. But they were all elaborate affairs with whiskers and goggle eyes: more the sort of thing that would appeal to a kid. Nothing, anyway, in the - the plain pink style.

There was a lot of stuff for kids' amateur theatricals, some old sparklers and pinwheels and the like, and a toy theatre ...'

'Penny plain and twopence coloured,' said Dr Fell with a wheeze of reminiscent pleasure. 'Gone for ever the glory of childhood. Wow! The grandeur of a toy theatre! In my innocent childhood days, Hadley, when I came trailing clouds of glory to the view (a thesis, by the way, which might have been open to considerable debate on the part of my parents); in my childhood days, I say, I owned a toy theatre with sixteen changes of scenery. Half of 'em, I am pleased to say, were gaol scenes. Why does the young imagination run so strongly to gaol scenes, I wonder? Why?'

'What the h.e.l.l's the matter with you?' demanded Hadley staring. 'Why the sentimentality?'

'Because I have suddenly got an idea,' said Dr Fell, gently. 'And, oh, my sacred hat, what an idea!' He remained blinking at Hadley. 'What about Drayman? Are you going to arrest him?'

'No. In the first place, I don't see how he could have done it, and I couldn't even get a warrant. In the second place - '

'You don't believe he's guilty?'

'H'm,' grunted Hadley, with an innate caution about doubting anybody's innocence. 'I don't say that, but I think he's likely to be less culpable than anybody else. Anyway, we've got to get a move on! Cagliostro Street first, then to interview several people. Finally - '

They heard the door - bell ring, and a sleepy maid - servant tumbled down to answer it.

'There's a gentleman downstairs, sir,' said Vida, poking her head into the room, 'who says he wants to see either you or the superintendent. A Mr Anthony Pettis, sir.'

CHAPTER 12.

THE PICTURE.

DR FELL, rumbling and chuckling and spilling ashes from his pipe like the Spirit of the Volcano, surged up to greet the visitor with a cordiality which seemed to put Mr Anthony Pettis much more at his ease. Mr Pettis bowed slightly to each of them.

'You must excuse me, gentlemen, for intruding so early,' he said. 'But I had to get it off my mind, and couldn't feel easy until I did. I understand you were - um - looking for me last night. And I had an unpleasant night of it, I can tell you.' He smiled.' My one criminal adventure was when I forgot to renew a dog licence, and my guilty conscience was all over me. Every time I went out with that confounded dog I thought every policeman in London was eyeing me in a sinister way. I began to slink. So in this case I thought I'd better hunt you out. They gave me this address at Scotland Yard.'

Dr Fell was already stripping off his guest's overcoat, with a gesture that nearly upset Mr Pettis, and hurling him into a chair. Mr Pettis grinned. He was a small, neat, starched man with a shiny bald head and a startlingly booming voice. He had prominent eyes, looking more shrewd with a wrinkle of concentration between them, a humorous mouth and a square, cleft chin. It was a bony face - imaginative, ascetic, rather nervous. When he spoke he had a trick of sitting forward in his chair, clasping his hands, and frowning at the floor.

'It's a bad business about Grimaud,' he said, and hesitated. 'Naturally I'll follow the formula of saying I wish to do everything I can to help. In this case it happens to be true.' He smiled again. 'Er - do you want me sitting with my face to the light, or what? Outside novels, this is my first experience with the police.'

'Nonsense,' said Dr Fell, introducing everybody. 'I've been wanting to meet you for some time; we've written a few things on the same lines. What'll you drink? Whisky? Brandy and soda?'

'It's rather early,' said Pettis doubtfully. 'Still, if you insist - thanks! I'm very familiar with your book on the supernatural in English fiction, doctor; you're a great deal more popular than I shall ever be. And it's sound.' He frowned. ' It's very sound. But I don't entirely agree with you (or Dr James) that a ghost in a story should always be malignant ..'

'Of course it should always be malignant. The more, more malignant,' thundered Dr Fell, s.c.r.e.w.i.n.g his own face up into a tolerably hideous leer, 'then the better. I want no sighing of gentle airs round my couch. I want no sweet whispers o'er Eden. I want BLOOD!' He looked at Pettis in a way which seemed to give the latter an uncomfortable idea it was his blood. 'Harrumph. Ha. I will give you rules, sir. The ghost should be malignant. It should never speak. It should never be transparent but solid. It should never hold the stage for long, but appear in brief vivid flashes like the poking of a face round a corner. It should never appear in too much light. It should have an old, an academic or ecclesiastical background; a flavour of cloisters or Latin ma.n.u.scripts. There is an unfortunate tendency nowadays to sneer at old libraries or ancient ruins, to say that the really horrible phantom would appear in a confectioner's shop or at a lemonade stand. This is what they call applying the "modern test". Very well, apply the test to real life. Now, people in real life honestly have been frightened out of their five wits in old ruins or churchyards. n.o.body would deny that. But, until somebody in actual life really does scream out and faint at the sight of something at a lemonade stand (other, of course than that beverage itself), then there is nothing to be said for this theory except that it is rubbish.'

'Some people would say,' observed Pettis, c.o.c.king one eyebrows, 'that the old ruins were rubbish. Don't you believe that good ghost stories can be written nowadays?'

'Of course they can be written nowadays, and there are more brilliant people to write 'em - if they would. The point is, they are afraid of the thing called Melodrama. So, if they can't eliminate the melodrama, they try to hide it by writing in such an oblique, upside - down way that n.o.body under heaven can understand what they are talking about. Instead of saying flat out what the character saw or heard, they try to give Impressions. It's as though a butler, in announcing guests at a ball, were to throw open the drawing - room doors and cry: "Flicker of a top - hat, vacantly seen, or is it my complex fixed on the umbrella stand faintly gleaming?" Now, his employer might not find this satisfactory. He might want to know who in blazes was calling on him. Terror ceases to be terror if it has to be worked out like an algebra problem. It may be deplorable if a man is told a joke on Sat.u.r.day night and suddenly bursts out laughing in church next morning. But it is much more deplorable if a man reads a terrifying ghost story on Sat.u.r.day night, and two weeks later suddenly snaps his fingers and realizes that he ought to have been scared. Sir, I say now - '

For some time an irritated superintendent of the C.I.D. had been fuming and clearing his throat in the background. Now Hadley settled matters by slamming his fist down on the table.

'Easy on, will you?' he demanded. 'We don't want to hear any lecture now. And it's Mr Pettis who wants to do the talking. So - ' When he saw Dr Fell's puffings subside into a grin, he went on, smoothly, ' As a matter of fact, it is a Sat.u.r.day night I want to talk about; last night.'

'And about a ghost?' Pettis inquired, whimsically. Dr Fell's outburst had put him entirely at his ease. 'The ghost who called on poor Grimaud?'

'Yes ... First, just as a matter of form, I must ask you to give an account of your movements last night. Especially between, say, nine - thirty and ten - thirty.'

Pettis put down his gla.s.s. His face had grown troubled again. ' Then you mean, Mr Hadley - after all, I am under suspicion?'

'The ghost said he was you. Didn't you know that?'

'Said he was - Good G.o.d, no!' cried Pettis, springing up like a bald - headed jack - in - the - box. 'Said he was me? I mean - er - said he was - hang the grammar! I want to know what you're talking about? What do you mean?' He sat down quietly and stared as Hadley explained. But lie fussed with his cuffs, fussed with his tie, and several times nearly interrupted.

'Therefore if you'll disprove it by giving an account of your movements last night -' Hadley took out his notebook.

'n.o.body told me about this last night. I was at Grimaud's after he was shot, but n.o.body told me,' said Pettis, troubled. 'As for last night, I went to the theatre: to His Majesty's Theatre.'

'You can establish that, of course.'

Pettis frowned. 'I don't know. I sincerely hope so. I can - tell you about the play, although I don't suppose that's much good. Oh, yes; and I think I've still got my ticket stub somewhere, or my programme. But you'll want to know if I met anybody I knew. Eh? No, I'm afraid not - unless I could find somebody who remembered me. I went alone. You see, every one of the few friends I have runs in a set groove. We know exactly where he is at most times, especially Sat.u.r.day evenings, and we don't try to change the orbit.' There was a wry twinkle in his eye. 'It's - it's a kind of respectable Bohemianism, not to say stodgy Bohemianism.'

'That,' said Hadley, 'would interest the murderer. What are these orbits?'

"Grimaud always works - excuse me; I can't get used to the idea that he's dead - always works until eleven. Afterwards you could disturb him as much as you liked; he's a night owl; but not before. Burnaby always plays poker at his club. Mangan, who's a sort of acolyte, is with Grimaud's daughter. He's with her most evenings, for that matter. I go the theatre or the films, but not always. I'm the exception.'

'I see. And after the theatre last night? What time did you get out?'

'Near enough to eleven or a little past. I was restless. I thought I might drop in on Grimaud and have a drink with him. And - well, you know what happened. Mills told me. I asked to see you, or whoever was in charge. After I had waited downstairs for a long time, without anybody paying any attention to me' - he spoke rather - snappishly - 'I went across to the nursing - home to see how Grimaud was getting on. I got there just as he died. Now, Mr Hadley, I know this is a terrible business, but I will swear to you - '

'Why did you ask to see me?'

'I was at the public - house when this man Fley uttered his threat, and I thought I might be of some help. Of course I supposed at the time it was Fley who had shot him; but this morning I see in the paper -'

'Just a minute! Before we go on to that, I understand that whoever imitated you used all your tricks of address, and so on, correctly? Good! Then who in your circle (or out of it) would you suspect of being able to do that?'

"Or wanting to do it,' the other said, sharply.

He sat back, being careful about the knife - crease of his trousers. His nervousness was clearly giving way before the twistings of a dry, curious, insatiable brain; an abstract problem intrigued him. Putting his finger - tips together he stared out of the long windows.

'Don't think I'm trying to evade your question, Mr Hadley,' he said, with an abrupt little cough. 'Frankly, I can't think of anybody. But this puzzle bothers me apart from the danger, in a way, to myself. If you think my ideas suffer from too much subtlety, or from too much plain d.a.m.ned nonsense, I'll put it up to Dr Fell. Let's suppose, for the sake of argument, that I am the murderer.'

He looked mockingly at Hadley, who had straightened up.

'Hold on! I am not the murderer, but let's suppose it. I go to kill Grimaud in some outlandish disguise (which by the way, I would rather commit a murder than be seen wearing). Hum! I indulge in all the rest of the tomfoolery. Is it likely that, after all these things, I would blatantly sing out my real name to those young people?'

He paused, tapping his fingers.

'That's the first view, the short - sighted view. But the very shrewd investigator would answer: "Yes, a clever murderer might do just that. It would be the most effective way of bamboozling all the people who had jumped to the first conclusion. He changed his voice a very little, just enough so that people would remember it afterwards. He spoke as Pettis because he wanted people to think it wasn't Pettis." Had you thought of that?'

'Oh, yes,' said Dr Fell, beaming broadly. 'It was the first thing I did think of.'

Pettis nodded. 'Then you will have thought of the answer to that, which clears me either way. If I were to do a thing like that, it isn't my voice I should have altered slightly. If the hearers accepted it to begin with, they might not later have the doubts I wanted them to have. But,' he said, pointing, 'what I should have done was to make one slip in my speech. I should have said something unusual, something wrong and obviously not like myself, which later they would have remembered. And this the visitor didn't do. His imitation was too thorough, which seems to excuse me. Whether you take the forthright view or the subtle one, I ran plead not guilty either because I'm not a fool or because I am.'

Hadley laughed. His amused gaze travelled from Pettis to Dr Fell, and he could keep his worried expression no longer.

'You two are birds of a feather,' he said. 'I like these gyrations. But I'll tell you from practical experience, Mr Pettis, that a criminal who tried anything like that would find himself in the soup. The police wouldn't stop to consider whether he was a fool or whether he wasn't. The police would take the forthright view - and hang him.'

'As you would hang me,' said Pettis, 'if you could find contributory evidence?'

'Exactly.'