‘Why did Ann Shapland also choose a sandbag to kill Mademoiselle Blanche?’ asked Miss Bulstrode.

‘For one thing, she could not risk a pistol shot in the school building, and for another she is a very clever young woman. She wanted to tie up this third murder with the second one, for which she had an alibi.’

‘I don’t really understand what Eleanor Vansittart was doing herself in the Sports Pavilion,’ said Miss Bulstrode.

‘I think one could make a guess. She was probably far more concerned over the disappearance of Shaista than she allowed to appear on the surface. She was as upset as Miss Chadwick was. In a way it was worse for her, because she had been left by you in charge—and the kidnapping had happened whilst she was responsible. Moreover she had pooh-poohed it as long as possible through an unwillingness to face unpleasant facts squarely.’

‘So there was weakness behind the façade,’ mused Miss Bulstrode. ‘I sometimes suspected it.’

‘She, too, I think, was unable to sleep. And I think she went out quietly to the Sports Pavilion to make an examination of Shaista’s locker in case there might be some clue there to the girl’s disappearance.’

‘You seem to have explanations for everything, Mr Poirot.’

‘That’s his speciality,’ said Inspector Kelsey with slight malice.

‘And what was the point of getting Eileen Rich to sketch various members of my staff?’

‘I wanted to test the child Jennifer’s ability to recognize a face. I soon satisfied myself that Jennifer was so entirely preoccupied by her own affairs, that she gave outsiders at most a cursory glance, taking in only the external details of their appearance. She did not recognize a sketch of Mademoiselle Blanche with a different hairdo. Still less, then, would she have recognized Ann Shapland who, as your secretary, she seldom saw at close quarters.’

‘You think that the woman with the racquet was Ann Shapland herself.’

‘Yes. It has been a one woman job all through. You remember that day, you rang for her to take a message to Julia but in the end, as the buzzer went unanswered, sent a girl to find Julia. Ann was accustomed to quick disguise. A fair wig, differently pencilled eyebrows, a “fussy” dress and hat. She need only be absent from her typewriter for about twenty minutes. I saw from Miss Rich’s clever sketches how easy it is for a woman to alter her appearance by purely external matters.’

‘Miss Rich—I wonder—’ Miss Bulstrode looked thoughtful.

Poirot gave Inspector Kelsey a look and the Inspector said he must be getting along.

‘Miss Rich?’ said Miss Bulstrode again.

‘Send for her,’ said Poirot. ‘It is the best way.’

Eileen Rich appeared. She was white faced and slightly defiant.

‘You want to know,’ she said to Miss Bulstrode, ‘what I was doing in Ramat?’

‘I think I have an idea,’ said Miss Bulstrode.

‘Just so,’ said Poirot. ‘Children nowadays know all the facts of life—but their eyes often retain innocence.’