‘You can put this one back,’ said Hemingway, unmoved by the compliment, and handing him the knife with the dusty hilt. ‘It hasn’t been touched. But this little fellow has been drawn out of its sheath very recently, or I’m a Dutchman!’ He held it up to the light, closely inspecting the hilt for finger-prints. No smudge on its polished surface was visible to the naked eye, and he added disgustedly: ‘What’s more, when the experts get on to it, they’ll find that it’s been carefully wiped. However, we won’t take any chances. Lend me that handkerchief of yours, will you?’

The Sergeant gave it to him. Carefully grasping the base of the hilt between his finger and thumb through the folds of the linen, Hemingway drew the knife from the sheath. It slid easily, a thin blade which revealed a slight stain close to the hilt. The Sergeant pointed a finger at this, and Hemingway nodded. ‘Overlooked that, didn’t he? Well, I fancy we have here the weapon that killed Nathaniel Herriard.’ Perceiving a look of elation on his subordinate’s face, he added dampingly: ‘Not that it’s likely to help us, but it’s nice to know.’

‘I don’t see why it shouldn’t help us,’ objected Ware. ‘It proves the murder was an inside job, anyway.’

‘Well, if that’s your idea of help, it isn’t mine,’ said Hemingway. ‘Of course it was an inside job! And a nice, high-class bit of work too! There won’t be any finger-prints on this. You have to hand it to our unknown friend. Thinks of everything. He chooses a weapon which nine people out of ten would stare at every day of their lives without attaching any importance to. He chooses a time when the house is full of visitors who all have their reasons for wanting old Herriard out of the way; and seizes the moment when everyone’s dressing for dinner to stab his host, and restore the knife at his leisure. It’s an education to have to do with this bird.’

The Sergeant gazed meditatively up at the wall over the fireplace. ‘Yes, and what’s more, he might have taken the knife at any time,’ he said. ‘There’s no sign he took the sheath as well.’

‘There’s every sign he didn’t.’

‘That’s what I mean. I daresay no one would have noticed if that knife had been taken out of the sheath quite a while before the murder was committed. It isn’t even as if it was on a line with your eyes: you have to look up to catch sight of it.’

‘What’s more important,’ said Hemingway, ‘is that it could have been put back at any time. After everyone had gone to bed, as like as not. So now perhaps you begin to see that the chances are that this nasty-looking dagger is going to rank as a matter of purely academic interest.’

Twelve

The Inspector had barely packed the knife and its sheath away into a case when Sturry entered the room, and stood upon the threshold with an expression of lofty resignation on his face. Hemingway, no respecter of persons, said: ‘Well, what do you want?’