‘So you’ve not seen your stepdaughter in over thirty years?’ Porter asked, his tone low and even.

Mary Locke shook her head. ‘Tash and I were never what I’d describe as close. She was a proper daddy’s girl when I came along and I think she saw me as just someone who was stealing his undivided attention away from her.’ She smiled wistfully. ‘Of course, I tried to show her I wasn’t a threat, but I never quite got through to her. Nathan had always been a workaholic before I met him, and she used to get the lion’s share of what free time he had.’ She shrugged. ‘I think perhaps she found it hard to share him at times.’

‘I can understand that must have been hard, Mrs Locke,’ said Styles, ‘but if we can focus more on where she might be now. Where does she work? Is there anyone else she’s close to who can tell us how to contact her?’

‘She had a hard time dealing with Nathan’s death. The last I heard she was teaching children to speak English in a school over in Poland. She’d travelled around Europe for a while after she finished school and ended up teaching somewhere near Kraków for about six months, so I guess it was easier to go back there again instead of sticking around here without her father.’

‘Do you have an address or phone number for the school?’ asked Styles.

She shook her head quickly. ‘Sorry, it was so long ago. I don’t know that she even gave me one.’

Porter pulled the envelope from his jacket, reversing the pictures they had taken from Natasha’s flat so they faced Mary Locke, and slid them across the glass tabletop towards her.

‘These are copies of pictures we found in Natasha’s flat, Mrs Locke. Could you point out Natasha for us, please?’

Mary Locke stared at them, only her eyes moving as she flicked between them. She made no move to pick them up. Porter waited patiently, and was on the verge of prompting her when she spoke.

‘That’s her in the denim jacket. Her and Nathan,’ she said, her gaze still fixed on the picture. ‘Nathan took her to see The Rolling Stones up in Aberdeen for her birthday, the year before he …’ She left the sentence unfinished.