‘Why not?’ Alleyn said amiably. ‘The answer’s regrettably simple. At the moment there are no deductions, only circumstances. And in point of fact there’s nothing, as far as we’ve gone, to contradict your theory of a sort of double-barrelled piece of hooliganism. Somebody gets the enchanting idea of rearranging the planks. Somebody else gets the even more amusing idea of dislodging a main sewer pipe. The victim of the earlier jeu d’esprit, by an unfortunate coincidence, becomes the victim of the second.’

‘Of course, if you put it like that –’

‘Coincidences do happen with unbelievable frequency. I sometimes think they’re the occupational hazards of police work. So far, for all we’ve seen, there’s no reason to suppose that Mr Cartell has not been the victim of one of them. Unless,’ Alleyn said, ‘you count this.’

He had a very quick, dexterous way of using his hands. With the least possible amount of fuss he had produced, laid upon Mr Period’s writing desk and lightly unfolded from his handkerchief, the gold case with a jewelled clasp. ‘I’m afraid,’ he said, ‘I shall have to keep it for the time being. But can you identify it?’

Mr Period gave a startled ejaculation and got to his feet.

At the same moment there was a tap on the door which at once opened to admit a girl and a tall young man.

‘I’m so sorry,’ Nicola said, ‘the front door was open and we thought – I’m awfully sorry.’ She stopped short, catching sight of the gold case lying on the handkerchief. ‘Oh,’ she exclaimed. ‘I am glad. Your lovely cigarette-case! You’ve found it!’

‘Ah – yes,’ Mr Period said with a little gasp. ‘Yes. It – it would appear so.’ He pulled himself together. ‘Nicola, my dear,’ he said, ‘may I introduce –’

‘But we’ve met!’ Nicola cried. ‘Often. Haven’t we? I was talking about you only yesterday. Bless my soul,’ she added gaily, ‘who, to coin a phrase, would have thought of meeting you?’

‘To coin another,’ Alleyn said mildly, ‘it’s quite a coincidence, isn’t it? Hallo, Nicola.’

III

‘Put it like this,’ Alleyn said. ‘I don’t say you’ll ever have to, but suppose you were asked to swear on oath that the window was shut during the Pixie episode, would you do it?’

Nicola said: ‘I’d have to, wouldn’t I? Because it was.’

‘Not a shadow of doubt?’

‘Not one. Alfred will say the same.’

‘I dare say.’

‘I wish I knew what you were up to,’ Nicola said, staring out into the garden.

‘I? I’m on my job.’

‘Yes, but are you peering into petty larceny or mucking into a – I’m sure I don’t know why I’m trying to be facetious – into a murder? Or do they tie in together? Or what?’

‘I don’t know. No more than you do.’

‘I suppose,’ Nicola said with some penetration, ‘you’re not very pleased to find me here.’

‘Not as enchanted as I would be to find you elsewhere.’