Their response to this statement had a delayed action. They behaved as actors do when they make what is technically known as a ‘double take’. There were a few seconds of blank witlessness followed by a sudden and violent reaction. Darcey and Percival shouted together that it would be exactly like Ben: Helena cried out inarticulately and Poole gave a violent ejaculation. The doctor crackled his newspaper and Martyn’s thoughts tumbled about in her head like dice. Jacko, alone, stared incredulously at Alleyn.

‘Do you mean,’ Jacko asked, ‘that we are to understand that Ben killed himself in such a way as to throw suspicion of murder upon one of us? Is that your meaning?’

‘No. For a time we wondered if this might be so but the state of the dressing-room, as I’d hoped I’d made clear, flatly contradicts any such theory. No. I believe the planner based the method on Bennington’s preoccupation with the other case and hoped we would be led to some such conclusion. If powder had not been spilt on the overcoat we might well have done so.’

‘So we are still—in the dark,’ Helena said and gave the commonplace phrase a most sombre colour.

‘Not altogether. I needn’t go over the collection of near-motives that have cropped up in the course of our interviews. Some of them sound far-fetched, others at least possible. It’s not generally recognized that, given a certain temperament, the motive for homicide can be astonishingly unconvincing. Men have been killed from petty covetousness, out of fright, vanity, jealousy, boredom, or sheer hatred. One or other of these motives lies at the back of this case. You all, I think, had cause to dislike this man. In one of you the cause was wedded to that particular kink which distinguishes murderers from the rest of mankind. With such beings there is usually some—shall I say, explosive agency, a sort of fuse—which, if it is touched off, sets them going as murder-machines. In this case I believe the fuse to have been a letter written by Otto Brod to Clark Bennington. This letter has disappeared and was probably burnt in his dressing-room. As the powder-pad may have been burnt. By his murderer.’

Poole said: ‘I can’t begin to see the sense of all this,’ and Helena said drearily: ‘Dark. In the dark.’