The Big Four. Агата Кристи

asked, ‘to find out what an unknown Englishman did on an evening two months ago?’

      ‘Very difficult, mon ami. But, as you know well, difficulties rejoice the heart of Hercule Poirot.’

      ‘You think the Big Four kidnapped him?’

      Poirot nodded.

      Our inquiries necessarily went over old ground, and we learnt little to add to what Mrs Halliday had already told us. Poirot had a lengthy interview with Professor Bourgoneau, during which he sought to elicit whether Halliday had mentioned any plan of his own for the evening; but we drew a complete blank.

      Our next source of information was the famous Madame Olivier. I was quite excited as we mounted the steps of her villa at Passy. It has always seemed to me so extraordinary that a woman should go so far in the scientific world. I should have thought a purely masculine brain was needed for such work.

      The door was opened by a young lad of seventeen or thereabouts, who reminded me vaguely of an acolyte, so ritualistic was his manner. Poirot had taken the trouble to arrange our interview beforehand, as he knew Madame Olivier never received anyone without an appointment, being immersed in research work most of the day.

      We were shown into a small salon, and presently the mistress of the house came to us there. Madame Olivier was a very tall woman, her tallness accentuated by the long white overall she wore, and a coif like a nun’s that shrouded her head. She had a long pale face, and wonderful dark eyes that burnt with a light almost fanatical. She looked more like a priestess of old than a modern Frenchwoman. One cheek was disfigured by a scar, and I remembered that her husband and co-worker had been killed in an explosion in the laboratory three years before, and that she herself had been terribly burned. Ever since then she had shut herself away from the world and plunged with fiery energy into the work of scientific research. She received us with cold politeness.

      ‘I have been interviewed by the police many times, messieurs. I think it hardly likely that I can help you, since I have not been able to help them.’

      ‘Madame, it is possible that I shall not ask you quite the same questions. To begin with, of what did you talk together, you and M. Halliday?’

      She looked a trifle surprised.

      ‘But of his work! His work, and also mine.’

      ‘Did he mention to you the theories he had embodied recently in his paper read before the British Association?’