‘Because that’s how it happens in the script. Marcus had recreated the dinner scene from The Lady Detective. Eleven courses, then murder over coffee.’ She shrugged. ‘Very unoriginal, in fact.’

‘That’s why you suspected murder. Because of a film.’ Larch’s tone was flat, disbelieving.

‘We suspected murder because we understand character. Narrative. Opportunity. And because we know, when it comes to murder, there’s no such thing as coincidence.’

Larch rubbed a hand across his forehead. Apparently this conversation was giving him a headache. Good.

‘Marcus wasn’t a nice person.’ She had to tread carefully if she wanted to avoid giving away all of their secrets. ‘It wasn’t a massive stretch to guess that someone had used his convention set-up to get rid of him.’

‘How?’ Larch asked.

‘I assume you noticed the spilled sugar in the Gate House?’

He looked confused, so Rosalind explained about the sugared violets at dinner that night – and how one of them was not a violet. Which led to explaining about Marcus’s tea.

‘Hmm,’ DCI Larch said.

‘Is that all you have to say?’

‘Would you rather I question you as to why you didn’t share this theory with us earlier?’ he asked.

‘It’s not a theory. It’s what happened.’

‘You believe.’ Larch put down his notebook, and rested his arms on his knees as he leant forward. ‘Or perhaps you’d prefer that I ask you about your relationship with Mr Hugh Davenport.’

Rosalind froze. ‘We’ve been friends for over forty years – I’m friends with him and his wife. I’m godmother to their daughter. What else is there to know?’

Larch got to his feet, looking down his long nose at her as she sat. If he’d been wearing glasses, he’d have looked like a mildly annoyed librarian. ‘I don’t have to give you another warning on the perils of lying to the police. Or pursuing your own, amateur investigation, instead of helping us with ours. Do I, Ms King?’

‘Of course not,’ she replied, primly. ‘I’ve already told you everything we’d figured out about the poison, haven’t I?’

‘Well, if you think of anything else—’

‘I’ll tell you. In the meantime, may I ask … did you find the murder weapon? I mean, whatever someone used to kill Clementine?’

‘Not yet.’ He sounded almost as annoyed by that as by her stories. ‘But we’re still looking. Aldermere is a large place.’

‘It is.’

‘And we have at least managed to find a record of her next of kin – a cousin, I believe – thanks to Miss Hill’s staff records.’

Of course. As secretary of the fan club, Felicity would have access to all the records Marcus did. Why hadn’t they thought of that?

Larch paused by the door. ‘In fact, you might be able to help me locate her. She’s here this weekend, I understand. A Miss Libby McKinley.’