‘You’re very quick on to the mark, M. Poirot. Come to see us about this Rosebank case almost before we know it is a case. What put you on to it?’
Poirot drew out the letter he had received and handed it to the inspector. The latter read it with some interest.
‘Interesting,’ he said. ‘The trouble is, it might mean so many things. Pity she couldn’t have been a little more explicit. It would have helped us now.’
‘Or there might have been no need for help.’
‘You mean?’
‘She might have been alive.’
‘You go as far as that, do you? H’m—I’m not sure you’re wrong.’
‘I pray of you, Inspector, recount to me the facts. I know nothing at all.’
‘That’s easily done. Old lady was taken bad after dinner on Tuesday night. Very alarming. Convulsions—spasms—whatnot. They sent for the doctor. By the time he arrived she was dead. Idea was she’d died of a fit. Well, he didn’t much like the look of things. He hemmed and hawed and put it with a bit of soft sawder, but he made it clear that he couldn’t give a death certificate. And as far as the family go, that’s where the matter stands. They’re awaiting the result of the post-mortem. We’ve got a bit further. The doctor gave us the tip right away—he and the police surgeon did the autopsy together—and the result is in no doubt whatever. The old lady died of a large dose of strychnine.’
‘Aha!’
‘That’s right. Very nasty bit of work. Point is, who gave it to her? It must have been administered very shortly before death. First idea was it was given to her in her food at dinner—but, frankly, that seems to be a washout. They had artichoke soup, served from a tureen, fish pie and apple tart.
‘Miss Barrowby, Mr Delafontaine and Mrs Delafontaine. Miss Barrowby had a kind of nurse-attendant—a half-Russian girl—but she didn’t eat with the family. She had the remains as they came out from the dining-room. There’s a maid, but it was her night out. She left the soup on the stove and the fish pie in the oven, and the apple tart was cold. All three of them ate the same thing—and, apart from that, I don’t think you could get strychnine down anyone’s throat that way. Stuff’s as bitter as gall. The doctor told me you could taste it in a solution of one in a thousand, or something like that.’
‘Coffee?’
‘Coffee’s more like it, but the old lady never took coffee.’
‘I see your point. Yes, it seems an insuperable difficulty. What did she drink at the meal?’
‘Water.’
‘Worse and worse.’
‘Bit of a teaser, isn’t it?’
‘She had money, the old lady?’
‘Very well to do, I imagine. Of course, we haven’t got exact details yet. The Delafontaines are pretty badly off, from what I can make out. The old lady helped with the upkeep of the house.’
Poirot smiled a little. He said, ‘So you suspect the Delafontaines. Which of them?’
‘I don’t exactly say I suspect either of them in particular. But there it is; they’re her only near relations, and her death brings them a tidy sum of money, I’ve no doubt. We all know what human nature is!’
‘Sometimes inhuman—yes, that is very true. And there was nothing else the old lady ate or drank?’
‘Well, as a matter of fact—’
‘Ah, voilà! I felt that you had something, as you say, up your sleeve—the soup, the fish pie, the apple tart—a bêtise! Now we come to the hub of the affair.’
‘I don’t know about that. But as a matter of fact, the old girl took a cachet before meals. You know, not a pill or a tablet; one of those rice-paper things with a powder inside. Some perfectly harmless thing for the digestion.’
‘Admirable. Nothing is easier than to fill a cachet with strychnine and substitute it for one of the others. It slips down the throat with a drink of water and is not tasted.’
‘That’s all right. The trouble is, the girl gave it to her.’
‘The Russian girl?’
‘Yes. Katrina Rieger. She was a kind of lady-help, nurse-companion to Miss Barrowby. Fairly ordered about by her, too, I gather. Fetch this, fetch that, fetch the other, rub my back, pour out my medicine, run round to the chemist—all that sort of business. You know how it is with these old women—they mean to be kind, but what they need is a sort of black slave!’