Jazz cut to the chase. ‘So the two of you became lovers?’

‘Not straight away, Inspector.’ Adele blushed. ‘We were friends for a long time first. Remember, he was Charlie’s housemaster and I was a married woman, hardly an appropriate relationship. I thought he was an attractive man; in fact, I think I had a bit of a crush on him, but I never supposed for a second that it was reciprocated. Then one day he told me it was.’

‘How long ago was this?’

‘Two years ago.’ Adele sighed. ‘Obviously, there was no alternative but to keep our relationship secret whilst Charlie was a pupil at the school. But we’d agreed that once Charlie left there was nothing to stop us being together. Sebastian was going to look for another position and I’d planned to leave William. We were planning a fresh start together.’

‘You wanted to spend the rest of your life with him?’

‘Yes.’ Adele nodded. ‘We like the same things, you see. We’re both outdoor people, sporty. I may not look it now, but I was a demon netball shooter in my day. I used to ride and swim and . . .’ Adele’s voice tailed off. ‘William was a city boy through and through. His idea of a day in the country was to find the nearest quaint pub and read the Sunday papers. Charlie’s death has precipitated the situation. I left William a couple of days ago. We’ve agreed to divorce.’ Adele shrugged. ‘Easy really. There was nothing left to stay for.’

‘I appreciate your candour, Mrs Cavendish,’ Jazz said. ‘Did you, at any point, give Sebastian a personal possession of yours . . . an item of jewellery, for example, as a . . . token of your affection?’

Adele looked surprised. ‘Yes, I did. I gave him my signet ring, the one that bears my family crest. And he gave me this.’ Adele held out the third finger on her left hand and showed Jazz a very pretty Russian wedding ring. ‘Of course, Sebastian couldn’t wear the ring in front of Charlie. He kept it in a drawer in his desk and wore it when we were together.’

‘He’s wearing it now, Adele. I’ve seen it,’ Jazz confirmed. ‘How long ago did you give it to him?’

‘Around the beginning of November, I should think.’ She rubbed her neck as if to remove the tension from it. ‘Gosh, that seems a long time ago. Before my son died. When life was relatively normal.’ She shook her head. ‘You can imagine how difficult it’s been for both of us since.’

‘Tell me how,’ Jazz encouraged.

Adele frowned. ‘Surely, you don’t need to ask, Inspector? My son died in Sebastian’s care. Need I say more? He’s wracked with guilt.’

‘Except . . . he wasn’t in Sebastian’s care, Adele.’ Jazz spoke slowly. ‘Sebastian was inexplicably absent from the house the night Charlie died.’

‘Exactly.’ Adele sat bolt upright, staring at Jazz. Suddenly she put her head in her hands and rocked back and forwards. ‘Don’t you see that makes it all the more terrible?’