‘I’ll answer that one,’ Alleyn said, ‘when you tell me what you did with Mr Period’s cigarette-case. Now don’t,’ he went on, raising a finger, ‘say you don’t know anything about it. I’ve seen the dining-room window. It can’t be opened from the outside. It was shut during luncheon. You and Miss Ralston examined the case by the window and left it on the sill. No one else was near the window. When the man came in to clear, the window was open and the case had gone.’

‘So he says.’

‘So he says and I believe him.’

‘Pardon me if I seem to be teaching you your job,’ Leonard said, ‘but if I was going to pinch this dreary old bit of tat, why would I open the window? Why not put it in my pocket there and then?’

‘Because you would then quite obviously be the thief, Mr Leiss. If you or Miss Ralston left it on the sill and returned by way of the garden path –’

‘How the hell –’ Leonard began, and then changed his mind. ‘I don’t accept that,’ he said. ‘I resent it, in fact.’

‘Did you smoke any of Mr Period’s cigarettes?’

‘Only one, thank you very much. Turkish muck.’

‘Did Miss Ralston?’

‘Same story. Now, look,’ Leonard began with a sort of spurious candour. ‘There’s such a thing as collusion, isn’t there? We left this morsel of antiquity on the sill. All right. This man – Alfred What-have-you – opens the window. The workmen in the lane get the office from him and it’s all as sweet as kiss your hand.’

‘And would you suggest that we search the men in the lane?’

‘Why not? Do no harm, would it?’

‘We might even catch them handing the case round after elevenses?’

‘That’s right,’ Leonard said coolly, ‘you might at that. Or, they might have cached it on the spot. You can search this room, or me or my car or my girlfriend. Only too pleased. The innocent don’t have anything to hide, do they?’ asked Leonard.

‘Nor do the guilty, when they’ve dumped the evidence.’

Leonard ran the tip of his tongue over his lips. ‘Fair enough,’ he said. ‘So what?’

‘Mr Leiss,’ Alleyn said, ‘the cigarette-case has been found.’

A second flickered past before Leonard, in a tone of righteous astonishment said: ‘Found! Well, I ask you! Found! so why come at me? Where?’

‘In my opinion, exactly where you dropped it. Down the drain.’

The door was thrust open. On the far side of the screen a feminine voice said: ‘Sorry, darling, but you’ll have to rouse up.’ The door was shut. ‘We are in a spot of bother,’ the voice continued as its owner came round the screen. ‘Old Cartell, dead as a doornail and down the drain.’

II

When Moppett saw Alleyn she clapped her hand to her mouth and eyed him over the top.