Finally Rosalind looked up, her eyes wide and her hands trembling. ‘I saw a letter like this – or at least, an envelope, with this handwriting on it. It was sitting on the telephone table on Friday night, so I took it up to Hugh. At the time, I couldn’t put my finger on what was strange about it, but I see it now. It had Hugh’s full name and address on it – but no stamp or postmark.’

‘It must have been hand delivered,’ Posy said, thoughtfully.

‘And Marcus was here at Aldermere that night,’ Rosalind confirmed.

‘So Marcus was blackmailing Hugh, and planning to blackmail Anton.’ That opened up a whole new world of possibilities for motive.

‘But what about?’ Posy asked. ‘I mean, I know what Anton was up to. But what was Hugh doing that was so blackmail worthy?’

Rosalind’s face drained of all remaining colour. ‘Isobel thinks … she told me she thinks he’s having an affair.’

‘An affair?’ Caro asked. ‘With whom?’

‘She didn’t say.’ But Caro would place money that Rosalind had an idea.

Posy got there first. ‘That’s why you were watching him and Clementine in the garden!’ she said.

Rosalind glared at her. ‘The tour wasn’t exactly riveting.’

‘Do you really think she could be Hugh’s mistress? Maybe that’s why she left.’ Caro could feel more pieces slotting into place. ‘I never bought that family emergency thing.’

‘I don’t know. I know Hugh. I don’t think he would. Well. Not with Clementine. She’s young enough to be his daughter.’ Caro wasn’t sure if Rosalind was trying to convince them or herself.

‘Granddaughter,’ Posy corrected, sounding disgusted. ‘But yeah, I could see her running if Hugh was being blackmailed about their relationship. And it would explain why he let her take the car.’

‘Was there anything else back there?’ Rosalind waved a hand towards the desk. ‘Any sign he was blackmailing anyone else?’

Caro hesitated. She should tell them about Marcus’s ledger, she knew. But surely this was all to do with the blackmail? There was nothing worth killing for in the ledger.

‘No. I think we have to assume that there might be more people he was blackmailing,’ she said. ‘This letter at least was never delivered, so perhaps Anton didn’t know Marcus had him in his sights.’

‘So he’d have no reason to murder him,’ Posy finished. ‘But Hugh did. He’d already received his letter.’

‘But as Caro says, he might not have been the only one,’ Rosalind added, hurriedly. She didn’t want to believe her beloved Hugh could have been responsible. It was almost laughable how she still doted on him after all these years, and all those stories.