devotedly as twins do, did everything alike, wore clothes alike, the same things seemed to happen to them, they had illnesses at the same time, they married about the same time or not very far removed in time. And eventually, as many twins do, instead of wanting to do everything in the same fashion and the same way, they wanted to do the opposite. To be as unlike each other as they could. And even between them grew a certain amount of dislike. More than that. There was a reason in the past for that. Alistair Ravenscroft as a young man fell in love with Dorothea Preston-Grey, the elder twin of the two. But his affection shifted to the other sister, Margaret, whom he married. There was jealousy then, no doubt, which led to an estrangement between the sisters. Margaret continued to be deeply attached to her twin, but Dorothea no longer was devoted in any way to Margaret. That seemed to me to be the explanation of a great many things. Dorothea was a tragic figure. By no fault of her own but by some accident of genes, of birth, of hereditary characteristics, she was always mentally unstable. At quite an early age she had, for some reason which has never been made clear, a dislike of children. There is every reason to believe that a child came to its death through her action. The evidence was not definite, but it was definite enough for a doctor to advise that she should have mental treatment, and she was for some years treated in a mental home. When reported cured by doctors, she resumed normal life, came often to stay with her sister and went out to Malaya at a time when they were stationed out there, to join them there. And there, again, an accident happened. A child of a neighbour. And again, although perhaps there was no very definite proof, it seems again Dorothea might have been responsible for it. General Ravenscroft took her home to England and she was placed once more in medical care. Once again she appeared to be cured, and after psychiatric care it was again said that she could go once more and resume a normal life. Margaret believed this time that all would be well, and thought that she ought to live with them so that they could watch closely for any signs of any further mental disability. I don’t think that General Ravenscroft approved. I think he had a very strong belief that just as someone can be born deformed, spastic or crippled in some way, she had a deformity of the brain which would recur from time to time and that she would have to be constantly watched and saved from herself in case some other tragedy happened.’
‘Are you saying,’ asked Desmond, ‘that it was she who shot both the Ravenscrofts?’
‘No,’ said Poirot, ‘that is not my solution. I think what happened was that Dorothea killed her sister, Margaret. They walked together on the cliff one day and Dorothea pushed Margaret over. The dormant obsession of hatred and resentment of the sister who, though so like herself, was sane and healthy, was too much for her. Hate, jealousy, the desire to kill all rose to the surface and dominated her. I think that there was one outsider who knew, who was here at the time that this happened. I think you knew, Mademoiselle Zélie.’
‘Yes,’ said Zélie Meauhourat, ‘I knew. I was here at the time. The Ravenscrofts had been worried about her. That is when they saw her attempt to injure their small son, Edward. Edward was sent back to school and I and Celia went to my pensionnat. I came back here – after seeing Celia settled in. Once the house was empty except for myself, General Ravenscroft and Dorothea and Margaret, nobody had any anxiety. And then one day it happened. The two sisters went out together. Dolly returned alone. She seemed in a very queer and nervous state. She came in and sat down at the tea-table. It was then General Ravenscroft noticed that her right hand was covered with blood. He asked her if she had had a fall. She said, “Oh no, it was nothing. Nothing at all. I got scratched by a rose-bush.” But there were no rose-bushes on the downs. It was a purely foolish remark and we were worried. If she had said