‘She might,’ said Inspector Bland slowly. ‘Actually, it’s the best thing she could do. You see, if she picks up a tray with cake and a fruit drink and tells everyone she’s taking that for the child down there – well, then, her presence is accounted for. She goes there and comes back and says the girl was alive at that time. We’ve taken her word for it. But if you remember, sir, and look again at the medical evidence, Dr Cook’s time of death is between four o’clock and quarter to five. We’ve only Miss Brewis’ word for it that Marlene was alive at a quarter past four. And there’s one curious point that came up about her testimony. She told me that it was Lady Stubbs who told her to take the cakes and fruit drink to Marlene. But another witness said quite definitely that that wasn’t the sort of thing that Lady Stubbs would think about. And I think, you know, that they’re right there. It’s not like Lady Stubbs. Lady Stubbs was a dumb beauty wrapped up in herself and her own appearance. She never seems to have ordered meals or taken an interest in household management or thought of anybody at all except her own handsome self. The more I think of it, the more it seems most unlikely that she should have told Miss Brewis to take anything to the Girl Guide.’

‘You know, Bland,’ said Merrall, ‘you’ve got something there. But what’s her motive, if so?’

‘No motive for killing the girl,’ said Bland; ‘but I do think, you know, that she might have a motive for killing Lady Stubbs. According to M. Poirot, whom I told you about, she’s head over heels in love with her employer. Supposing she followed Lady Stubbs into the woods and killed her and that Marlene Tucker, bored in the boathouse, came out and happened to see it? Then of course she’d have to kill Marlene too. What would she do next? Put the girl’s body in the boathouse, come back to the house, fetch the tray and go down to the boathouse again. Then she’s covered her own absence from the fête and we’ve got her testimony, our only reliable testimony on the face of it, that Marlene Tucker was alive at a quarter past four.’

‘Well,’ said Major Merrall, with a sigh, ‘keep after it, Bland. Keep after it. What do you think she did with Lady Stubbs’ body, if she’s the guilty party?’

‘Hid it in the woods, buried it, or threw it into the river.’

‘The last would be rather difficult, wouldn’t it?’

‘It depends where the murder was committed,’ said the inspector. ‘She’s quite a hefty woman. If it was not far from the boathouse, she could have carried her down there and thrown her off the edge of the quay.’