“To return to the timing of these killings,” said Poirot. “The police doctor’s view was that death occurred in all three cases between four and half past eight. Circumstantial evidence later narrowed this down to between a quarter past seven and ten past eight. Eh bien, let us examine that circumstantial evidence. The waiter Rafal Bobak saw all three victims alive at a quarter past seven when he made his delivery to Room 317, and Thomas Brignell saw Richard Negus alive at half past seven in the hotel lobby, when Negus complimented Brignell on his efficiency, asked him to make sure the tea and cakes were put on his bill, and requested a sherry. So it seems that none of the killings can have happened before fifteen minutes past seven, and that the murder of Richard Negus cannot have happened before half past.

“However, there are a handful of details that do not fit to make the neat picture. First, there is the disappearing food that we know was not eaten by Harriet Sippel, Ida Gransbury and Richard Negus. I do not believe that anyone about to kill for the first time would imagine he might first want to eat a scone. So why order food that one has no intention of eating unless to establish in the eyes of a witness that you are alive at a quarter past seven? And why should it be necessary for our three victims to be seen alive at that specific time? I can think of just one possible explanation that is consistent with Jennie Hobbs’s story: if our conspirators knew, somehow, that Nancy Ducane had no credible alibi for the hour between a quarter past seven and a quarter past eight, they might have wished to make it look as if that was when the killings took place. But Nancy Ducane has a very solid alibi for that hour, does she not, Lady Wallace?”

Louisa Wallace rose to her feet. “Yes, she does. She was with me and my husband until around ten o’clock that evening, dining in our home.”

“Merci beaucoup, madame. Alors, I can think of only one reason why it should be of such vital importance to create the appearance of the three deaths having taken place between a quarter past seven and ten past eight: between those times, Jennie Hobbs has an unshakeable alibi. I, Hercule Poirot, know perfectly well that she cannot have been at the Bloxham Hotel then. She was with me at Pleasant’s Coffee House between thirty-five and fifty minutes past seven, and I have already spoken about the traveling times involved.

“I put all this together with my conviction that the three deaths did not occur between a quarter past seven and ten minutes past eight, and I begin to wonder: why go to such trouble to make it look as if Jennie Hobbs could not have committed these murders, unless in fact she did commit them?”