The paint-box had been opened. A dollop of Emerald Oxide of Chromium and one of Ivory Black had been squeezed out on the protective under-lid that separated the paints from a compartment designed to hold sketching-boards. A large brush had been used, and had been dipped first in the green and then in the black.

‘You know,’ said Paul, ‘this brush ought to have finger-prints on it.’ He looked rather shyly at Troy. ‘Oughtn’t it?’ he added.

‘Well, I suppose Roderick would say so,’ she agreed.

‘I mean, if it has and if we could get everybody’s to compare, that would be pretty conclusive, wouldn’t it? What’s more, it’d be damned interesting.’

‘Yes, but I’ve a notion fingerprints are not as easy as all that.’

‘I know. The hand would move about and so on. But look! There is some green paint smeared up the handle. I’ve read about it. Suppose we asked them to let us take their prints. They couldn’t very well refuse.’

‘Oh, Paul, let’s!’ cried Fenella.

‘What do you think, Mrs Alleyn?’

‘My dear chap, you mustn’t imagine I know anything about it. But I agree it would be interesting. I do know more or less how they take official prints.’

‘I’ve read it up quite a bit,’ said Paul. ‘I say. Suppose we did get them to do it, and suppose we kept the brush and the box intact—well—well, would—do you think—?’

‘I’d show them to him like a shot,’ said Troy.

‘I say, that’s perfectly splendid,’ said Paul. ‘Look here, I’ll damn well put it to them in the morning. It ought to be cleared up. It’s all bloody rum, the whole show, isn’t it? What d’you say, Mrs Alleyn?’

‘I’m on,’ said Troy.

‘Glory!’ said Fenella. ‘So’m I. Let’s.’

‘OK,’ said Paul, gingerly wrapping the brush in rag. ‘We’ll lock up the brush and box.’

‘I’ll take them up with me.’

‘Will you? That’s grand.’

They locked the portrait in the property-room, and said goodnight conspiratorially. Troy felt she could not face another session with the Ancreds, and sending her excuses, went upstairs to her room.