'How horrible! Poor thing. Of course leading the life she did she was bound to come to a bad end.'

'That's what the commissaire de police at Toulon said.'

'Do they know who did it?'

'No, but I do. I think you killed her.'

She gave me a stare of amazement.

'What are you talking about?' Then with the ghost of a chuckle: 'Guess again; I have a cast-iron alibi.'

'I ran across her at Toulon last summer. I had a long talk with her.'

'Was she sober?'

'Sufficiently. She told me how it happened that she'd disappeared so unaccountably just a few days before she was going to be married to Larry.'

I noticed Isabel's face stiffen. I proceeded to tell her exactly what Sophie had told me. She listened warily.

'I've thought of her story a good deal since then and the more I've thought about it the more convinced I am that there's something fishy about it. I've lunched here twenty times and you never have liqueurs for luncheon. You'd been lunching alone. Why should there have been a bottle of zubrovka on the tray with the coffee-cup?'

'Uncle Elliott had just sent it to me. I wanted to see if I liked it as much as when I'd had it at the Ritz.'

'Yes, I remember how you raved about it then. I was surprised, as you never drink liqueurs anyway; you're much too careful of your figure for that. I had at the time an impression that you were trying to tantalize Sophie. I thought it was just malice.'

'Thank you.'

'On the whole you're very good at keeping appointments. Why should you have gone out when you were expecting Sophie for something so important to her and interesting to you as a fitting of her wedding dress?'

'She told you that herself. I wasn't happy about Joan's teeth. Our dentist is very busy and I just had to take the time he could give me.'

'When one goes to a dentist one makes the next appointment before leaving.'

'I know. But he called me up in the morning and said he had to break it, but could give me three o'clock that afternoon instead, so of course I jumped at it.'

'Couldn't the governess have taken Joan.'

'She was scared, poor darling, I felt she'd be happier if I went with her.'

'And when you came back and found the bottle of zubrovka three parts empty and Sophie gone, weren't you rather surprised?'

'I thought she'd got tired of waiting and gone on to Molyneux's by herself. I couldn't make it out when I went there and they told me she hadn't been.'

'And the zubrovka?'

'Well, I did notice that a good deal had been drunk. I thought Antoine had drunk it and I very nearly spoke to him about it, but Uncle Elliott was paying for him and he was a friend of Joseph's, so I thought I'd better ignore it. He's a very good servant and if he takes a little nip now and then who am I to blame him?'

'What a liar you are, Isabel.'

'Don't you believe me?'

'Not for a moment.'

Isabel got up and walked over to the chimney-piece. There was a wood fire and it was pleasant on that dreary day. She stood with one elbow on the mantel-shelf in a graceful attitude which it was one of her most charming gifts to be able to assume without any appearance of intention. Like most French women of distinction she dressed in black in the daytime, which peculiarly suited her rich colouring, and on this occasion she wore a dress the expensive simplicity of which displayed her slender figure to advantage. She puffed at her cigarette for a minute.

'There's no reason why I shouldn't be perfectly frank with you. It was most unfortunate that I had to go out and of course Antoine should never have left the liqueur and the coffee-things in the room. They ought to have been taken away when I went out. When I came back and saw the bottle was nearly empty of course I knew what had happened, and when Sophie disappeared I guessed she'd gone off on a bat. I didn't say anything about it because I thought it would only distress Larry, and he was worried enough as it was.'

'Are you sure the bottle wasn't left there on your explicit instructions?'

'Quite.'

'I don't believe you.'

'Don't then.' She flung the cigarette viciously into the fire. Her eyes were dark with anger. 'All right, if you want the truth you can have it and to hell with you. I did it and I'd do it again. I told you I'd stick at nothing to prevent her from marrying Larry. You wouldn't do a thing, either you or Gray. You just shrugged your shoulders and said it was a terrible mistake. You didn't care a damn. I did.'

'If you'd left her alone she'd be alive now.'

'Married to Larry and he'd be utterly miserable. He thought he'd make a new woman of her. What fools men are! I knew that sooner or later she'd break down. It stuck out a mile. You saw yourself when we were all lunching together at the Ritz how jittery she was. I noticed you looking at her when she was drinking her coffee; her hand was shaking so, she was afraid to take the cup with one hand, she had to put both her hands to it to get it up to her mouth. I noticed her watching the wine when the waiter filled our glasses; she followed the bottle with those horrible washed-out eyes of hers like a snake following the fluttering of a new-fledged chick and I knew she'd give her soul for a drink.'

Isabel faced me now, her eyes flashing with passion, and her voice was harsh. She couldn't get the words out quickly enough.

'The idea came to me when Uncle Elliott made all that fuss about that damned Polish liqueur. I thought it beastly, but I pretended it was the most wonderful stuff I'd ever tasted. I was certain that if she got a chance she'd never have the strength to resist. That's why I took her to the dress show. That's why I offered to make her a present of her wedding dress. That day, when she was going to have the last fitting, I told Antoine I'd have the zubrovka after lunch and then I told him I was expecting a lady and to ask her to wait and offer her some coffee and to leave the liqueur in case she fancied a glass. I did take Joan to the dentist's, but of course we hadn't an appointment and he couldn't see us, so I took her to a newsreel. I'd made up my mind that if I found Sophie hadn't touched the stuff I'd make the best of things and try to be friends with her. That's true, I swear it. But when I got home and saw the bottle I knew I'd been right. She'd gone and I'd have bet any money in the world she'd gone for good.'

Isabel was actually panting when she finished.

'That's more or less what I imagined had happened,' I said. 'You see, I was right; you cut her throat as surely as if you'd drawn the knife across it with your own hands.'

'She was bad, bad, bad. I'm glad she's dead.' She threw herself into a chair. 'Give me a cocktail, damn you.'

I went over and mixed another.

'You are a mean devil,' she said as she took it from me. Then she allowed herself to smile. Her smile was like a child's that knows it's been naughty, but thinks it can wheedle you by its ingenuous charm not to be cross. 'You won't tell Larry, will you?'

'I wouldn't dream of it.'

'Cross your heart? Men are so untrustworthy.'

'I promise you I won't. But even if I wanted to, I shouldn't have an opportunity as I don't suppose I shall ever see him again in my life.'

She sat bolt upright.

'What do you mean?'

'At this moment, he's on a freighter, either as a deck hand or a stoker, on his way to New York.'

'You don't mean that? What a strange creature he is! He was up here a few weeks ago for something to do with his book that he had to look up at the public library, but he never said a word about going to America. I'm glad; that means we shall see him.'

'I doubt it. His America will be as remote from your America as the Gobi desert.'

Then I told her what he had done and what he intended to do. She listened to me open-mouthed. Consternation was written on her face. She interrupted me now and then with an interjection 'He's crazy. He's crazy.' When I had finished she hung her head and I saw two tears trickle down her cheeks.