Grusche continued, ‘We were sitting at the top of the cliff, Jimmy. There was that strange early morning light, which you only get at this time of the year. There was so much noise. All those seabirds shrieking around our heads. But I could still hear the woman laughing. I picked up a boulder and I hit her with it.’ Another pause. ‘She fell awkwardly and seemed somehow crumpled and disfigured. I like lovely images. You know that, Jimmy. You know I could have been an artist myself. Fran always told me I had great potential, but I was happy to sacrifice that for my son. I dragged Eleanor into the middle of the loch, so that she looked like a picture. Someone might take some pleasure from the striking image, at least. She was a beautiful woman.’

‘What did you do then? After you’d thrown her cloak and shoes over the cliff and you’d torn the photograph into little pieces.’

‘I went home,’ Grusche said. ‘I lay next to my snoring husband. I went to sleep.’ She reached out and took one of the biscuits, then nibbled it as if she was judging its quality. Willow was astonished at how calm she seemed. There was another minute of complete silence.

‘Did you tell Lowrie what happened?’ Perez’s voice was sharper now. ‘I mean, has he known for the last week that his mother is a murderer?’

‘No!’ The same explosive retort. ‘Of course not.’

‘But you must have asked him what he was doing with Eleanor in Lerwick. You would have wanted to know.’

For the first time Grusche seemed less sure of her ground. ‘He said he was there as a friend, helping Eleanor with some project at work. I told him that he must keep that secret, that you would suspect him of killing her if you knew that he’d met her in Lerwick without telling anyone.’

‘And Lowrie did what he was told,’ Perez murmured. ‘Of course he did. First you and then Caroline making decisions for him. He’d never had to think for himself.’

Willow wondered if Lowrie had guessed at his mother’s involvement in Eleanor’s death. Perhaps she was so perfect in his eyes that he couldn’t contemplate the possibility of her being a murderer. Certainly he hadn’t asked Grusche any awkward questions. Willow was reminded of the way that Charles and David had kept their relationship intact by ignoring unpleasantness – anything that was difficult or uncomfortable.

‘What about Hillier?’ Perez was saying. ‘Why did he have to die?’

‘He was there that night,’ Grusche said. ‘He saw me walk up the path with Eleanor. And come down all alone.’

‘He was blackmailing you?’

‘And that shows just how ridiculous he was!’ Grusche spat out the words. ‘As if we’d have any money to give him.’