‘Yes. On the 10th, the first morning when I set this pose, I arranged it to look as if the figure had been murdered in exactly this way. Cedric Malmsley, one of my students, was doing a book illustration of a similar incident.’ She paused for a moment, looking into the fire. ‘During the rest they began arguing about the possibilities of committing a crime in this way. Hatchett, another student, got a knife that is in the junk-room, and shoved it through from underneath. Ormerin helped him. The throne was roughly knocked up for me in the village and the boards have warped apart. The blade is much narrower at the tip than at the hilt. The tip went through easily, but he hammered at the hilt to force it right up. The boards gripped the wider end. You will see all that when you look at it.’

‘Yes.’ Alleyn made a note in his book and waited.

‘The drape was arranged to hide the knife and it all looked quite convincing. Sonia was—she was quite—frightened. Hatchett pulled the knife out—it needed some doing—and we put everything straight again.’

‘What happened to the knife?’

‘Let me see. I think Hatchett put it away.’

‘From a practical point of view, how could you be sure that the knife would come through at exactly the right place to do what it has done?’

‘The position of the figure is chalked on the floor. When she took the pose, Sonia fitted her right hip and leg into the chalk marks, and then slid down until the whole of her right side was on the floor. One of the students would move her until she was inside the marks. Then she let the torso go over until her left shoulder touched the floor. The left hip was off the ground. I could draw it for you.’

Alleyn opened his notebook at a clean page and handed it to her with his pencil. Troy swept a dozen lines down and gave it back to him.

‘Wonderful!’ said Alleyn, ‘to be able to do that—so easily.’

‘I’m not likely to forget that pose,’ said Troy dryly.

‘What about the drape? Didn’t that cover the chalk-marks?’

‘Only in places. It fell from a suspension-point on the cushion to the floor. As she went down, she carried it with her. The accidental folds that came that way were more interesting than any laboured arrangement. When the students made their experiment they found the place where the heart would be, quite easily, inside the trace on the floor. The crack passed through this point. Hatchett put a pencil through the crack and they marked the position on the underside of the throne.’

‘Is there any possibility that they repeated this performance for some reason on Friday and forgot to withdraw the dagger?’