‘Will she worry about you being away for several nights?’ she said.

‘I’ll tell her I’m spending a few nights at Julia’s place. I’ll see her during the day, so it won’t be a problem.’ He crossed his arms and stared at her defiantly.

And that’s that, thought Laura. If only she could meet the mother. She was sure that old or not, she would want to help her son.

Sam told Shields about Professor Hugh Mackenzie, who was making a special trip from Scotland to discuss his case. ‘We are making every effort to help you, you know. So please, don’t despair. We’ll get to the bottom of this, and you’ll be back to normal again.’

Laura wrote down the address and telephone number of the clinic for him. ‘I’ll ring them now, before you leave, then you’ll know what time to be there.’ She made the call, wishing she could hand this man over to them permanently. Then she felt guilty for wishing it. ‘Be there at eight this evening, Mr Shields. They’ll be expecting you.’

Shields finally drove away. After he’d gone, she and Sam sat in silence for a few moments.

‘I see what you mean, Laura,’ said Sam. ‘What on earth is going on in that head of his?’

When she didn’t answer, Sam squeezed her arm. ‘You were right to call me in. I think your Mr Shields has another agenda altogether here — my alarm bells are ringing very loudly.’

Oh, thank goodness, Laura thought, so I wasn’t imagining things!

Laura looked at her watch. ‘I have a couple of sessions with PCs who have suffered recent traumas, then I have to brief Superintendent Ruth Crooke on how they’re doing. As soon as I’m through with that, I thought I might have a word with the crew that went out to the filling station last night. I’d like to hear their take on Mr Shields’s behaviour. Is that being unethical?’

‘Not in the slightest,’ said Sam. ‘You’re concerned for his safety, that’s all. You aren’t divulging anything to them, just asking what they witnessed. There’s no problem in that.’

‘Good.’ Laura didn’t mention it, but she thought she might drive past Shields’s house on her way back. After Sam had expressed his own doubts about her client, she felt more confident. She needed to find out what Frederick Shields was really like, not what he chose to tell her.

While Sam unpacked, Laura switched on her computer. It would be useful to know what type of woman Shields’s partner Julia was. He had told her that she was a teacher at Saltern Academy, so she found the website, which had a page called ‘Meet Our Staff’. She scrolled down the list of names and photographs, looking for a Julia.