‘We believe a Sister Margaret Wilde did, and were told she now lives here,’ Jane said.

‘Yes, she does. Sister Margaret’s been with us for about three years.’

‘If it’s convenient we’d like to speak with her, please.’

Mother Lynne looked concerned. ‘Sister Margaret is in our care wing. She’s seventy-seven now and has dementia.’

‘Then she’ll have no memory of her time at the Sisters of Mercy, I expect,’ Jane said. It looked as if they’d made a wasted journey.

‘She has good days and bad days with her memory,’ Mother Lynne said. ‘She can also be quite cantankerous at times. I’m more concerned about the effect discussing a murder might have on her peace of mind.’

‘Is she aware of our press appeal?’ Jane asked.

‘Not as far as I know. She doesn’t have a television and has no interest in the newspapers. Most of the time she listens to music on her old record player and reads books . . . though it takes her weeks to get through them as she often forgets what’s happened and has to start all over again.’

Jane nodded. ‘I understand your concerns, Mother Superior. We were told Sister Margaret knew our victim. It’s also possible she reported her to Bromley police as a missing person. I’m happy not to mention that our victim was murdered, but anything Sister Margaret can remember might help us to find who was responsible for her death.’

Mother Lynne paused for thought before answering. ‘To engage with Sister Margaret, you will need to speak slowly and clearly, using simple words and short sentences.’

Jane nodded. ‘We won’t cause her any undue stress.’

As they walked along the care wing corridor Jane could hear the sound of loud music coming from one of the rooms.

‘Someone likes their music,’ Jane remarked.

Mother Lynne sighed. ‘It’s coming from Sister Margaret’s room. We’re constantly having to tell her to turn it down. It upsets the other residents on the wing.’

Boon whispered to Jane, ‘It’s “And the Glory of the Lord” from Handel’s Messiah.’

‘Another opera?’ Jane said, wondering if he was pulling her leg again.

‘Actually, technically it’s an oratorio,’ he added.

Sister Margaret’s room was modestly furnished with a reclining hospital bed, a comfortable armchair, a wardrobe, and a chest of drawers with six small wood carvings of animals on it.

Sister Margaret was sitting in the armchair next to the bed, staring out of the window. She was a plump woman with long grey hair and a lined face. Jane thought she looked a lot older than Mother Lynne had said.

‘Hello, Sister Margaret. How are you today?’ Mother Lynne said.

Sister Margaret continued staring out of the window and said nothing. Mother Lynne turned the record player on the bedside cabinet off.

Sister Margaret glared at her. ‘Why did you do that?’