‘What kind of a ventilator?’ asked Hemingway.

‘The ordinary sort, opening outwards, which you often get above a casement-window.’

‘Big enough for anyone to get in through it?’

The Chief Constable looked at Inspector Colwall, who said slowly: ‘Well, it is, and it isn’t, if you take my meaning. A man would have to be pretty small to do it, and, what’s more, he’d need to be clever. It isn’t as though the room’s on the ground-floor, you see. What with having to climb up to it, and then squirm in without making any noise – well, I don’t see how it could have been done, I’m bound to confess. Nor I couldn’t discover any signs of footprints on the sill, but you can’t go by that entirely, for it was snowing hard all yesterday evening, and they might easily have been covered up.’

‘Any finger-prints?’

‘Only on the insides of the windows, and they were Ford’s, just as you’d expect. It was he who shut the windows after tea, and drew the curtains.’

‘What about the door-keys?’

‘That’s just it,’ said the Major. ‘We’ve had them carefully examined, and we can’t detect any of the scratches you’d expect to find if they’d been turned in the locks from outside.’

‘That’s queer,’ said Hemingway, with the bird-like look in his eye which his Sergeant knew betokened lively interest. ‘Sounds like a classy case, after all. Any signs of a struggle in the room, sir?’

‘None whatsoever.’

‘Looks as though he wasn’t expecting trouble from his visitor, then. Those the photographs, sir? Thank you.’ He considered them for a moment or two, and remarked: ‘Still in his day-clothes.’

‘Yes; there were no signs that he’d started to change. Ford had prepared his bath, and laid out his dinner-jacket and things.’

‘He didn’t have this Ford in to help him dress?’

‘Apparently he did sometimes, but not always. He rang if he wanted Ford.’

‘Oh! Weapon?’

‘The doctors are agreed that the blow was struck with a thin, sharp instrument, probably a knife. You’ll see the position of the wound. There was scarcely any external bleeding, but death, I’m informed, must have followed within a very few minutes.’

‘I see, sir. Weapon not found?’

‘Not so far. But to my mind it hasn’t been looked for,’ said the Major, casting a severe glance towards Inspector Colwall.

The Inspector reddened. ‘It was looked for in the deceased’s room, sir, but you know as well as I do that it’s a very big house, and what with that, and the number of people all staying there, with their baggage – well, it’s a tall order to find the weapon, and I didn’t like to turn the place upside-down.’

The Major looked unconvinced, but Hemingway said: ‘No, you’d have been at it all night and half today, I daresay.’

‘Well, that’s where it is,’ said Colwall gratefully.

‘I don’t know that the weapon’s going to interest me much,’ pursued Hemingway. ‘What with all these thrillers that get written nowadays by people who ought to know better than to go putting ideas into criminals’ heads, there’s no chance of any murderer forgetting to wipe off his finger-prints. Sickening, I call it. Now, how do you figure the murderer got into that room, Inspector?’