‘I don’t see how it could have been. I suppose old Pomeroy bleated about his injuries when he went screeching up to the Yard. I think he’s right. Far as I can see the old man did take reasonable precautions. Well, perhaps not that, the stuff ought never to have been left on the premises. But I don’t see how, twenty-four hours after he’d stowed the bottle away in the cupboard, he could have infected that dart accidentally. We’ve printed the cupboard. It’s got his prints on it and nobody else’s.’

‘Oh,’ said Alleyn, ‘then it isn’t a case of somebody else having tampered with the bottle and been too scared to own up.’

‘No.’

‘How many sets of Pomeroy’s prints are on the cupboard door?’

‘Several. Four good ones on the knob. And he turned the key in the top cupboard when he put the cyanide away. His print’s on the key all right and you can’t do the pencil trick, for I’ve tried. It’s a fair teaser.’

‘Any prints on the bottle?’

‘None. But he explained he wore gloves and wiped the bottle.’

‘The cupboard door’s interesting.’

‘Is it? Well, when he opened the parcel of darts he broke the seals. I got hold of the wrapping and string. The string had only been tied once and the seals have got the shop’s mark on them.’

‘Damn good, Nick,’ said Alleyn. Mr Harper looked a little less jaundiced.

‘Well, it goes to show,’ he admitted. ‘The dart was OK when old Pomeroy unpacked it. Then young Will and Parish handled the darts, and then Legge tried them out. Next thing—one of ‘em sticks into deceased’s finger and in five minutes he’s a corpse.’

‘The inference being—?’

‘God knows! They found cyanide on the dart but how the hell it got there’s a masterpiece. I suppose old Pomeroy’s talked Legge to you.’

‘Yes.’

‘Yes. Well, Legge had his coat off and his sleeves rolled up. Cubitt and young Pomeroy swear he took the darts with his left hand and held them point outward in a bunch while he tried them. They say he didn’t wait any time at all. Just threw them into the board, said they were all right, and then waded in with his trick. You see, they were all watching Legge.’

‘Yes.’

‘What about the other five, Super?’ asked Fox. ‘He used six for the trick, didn’t he?’

‘Meaning one of them might have contrived to smear cyanide on one dart, while they looked at the lot?’

‘It doesn’t make any sort of sense,’ said Alleyn. ‘How was Cubitt or young Pomeroy to know Legge was going to pink Watchman?’

‘That’s right,’ agreed Harper, relapsing. ‘So it must be Legge but it couldn’t be Legge; so it must be accident but it couldn’t be accident. Funny, isn’t it?’

‘Screamingly.’