The Sergeant sighed, and waited patiently.

‘While I was prowling round the house today, more like a Boy Scout than a policeman, I treated myself to a nice quiet review of the case.’ Hemingway poised a piece of cheese on his knife, and raised it to his mouth. ‘And taking one thing with another, and adding them up together with a bit of flair, and a knowledge of psychology, I came to the conclusion that I was being led around by the nose. Now, that’s a thing I don’t take kindly to at all. What’s more, the Department wouldn’t like it.’ He put the cheese into his mouth, and munched it.

‘Who’s leading you around by the nose?’ asked the Sergeant, intent, but bewildered.

Hemingway washed the cheese down with some beer. ‘Kind old Uncle Joseph,’ he answered.

The Sergeant frowned. ‘Trying to put you off young Stephen’s scent? But –’

‘No,’ said Hemingway. ‘Trying to put me off his own scent.’

‘But, good lord, Chief, you don’t think he did it, do you?’ gasped the Sergeant.

Hemingway regarded him pityingly. ‘You can’t help not having flair, because it’s French, and you wouldn’t understand it,’ he said, ‘but you ought to be able to do ordinary arithmetic.’

‘I can,’ said the Sergeant, nettled. ‘Begging your pardon, sir, I can add two and two together and make it four as well as anyone. What I can’t do is to make it five. But I daresay that’s French too.’

‘No,’ said Hemingway, quite unruffled. ‘That’s Vision, my lad. You haven’t got it.’

‘No, but I know what it is,’ retorted the Sergeant insubordinately. ‘It’s seeing things, like you warned me you were beginning to.’

‘One of these days I shall get annoyed with you,’ said Hemingway. ‘You’ll be reduced to the ranks, very likely.’

‘But, Chief, he couldn’t have done it!’ the Sergeant pointed out.

‘If it comes to that, they couldn’t any of them have done it.’

‘I know; but he’s the one man who’s got an alibi from the moment Herriard went upstairs to the moment when he was found dead!’

‘When you put it to me like that, I can’t make out why I didn’t suspect him at the outset,’ said Hemingway imperturbably.

The Sergeant said almost despairingly: ‘He was talking to Miss Clare through the communicating door into the bathroom. You aren’t going to tell me you suspect her of being mixed up in it?’

‘No, I’m not. What I am going to tell you, though, is that when you get a bunch of suspects only one of whom has had the foresight to provide himself with an alibi, you want to keep a very sharp eye on that one. I admit I didn’t, but that was very likely because you distracted me.’

The Sergeant swallowed something in his throat. ‘Very likely,’ he agreed bitterly.