‘Our work was finished. We left the phone in the office. To return to the Snuggery was not an option to be considered and fortunately we had locked the door behind us. We left the house through the front door and returned to our separate hotels. Unfortunately, it was impossible to leave the island immediately, which is what I wished to do, but now our director of operations has been in contact with the Guernsey police department and we go tonight.’

Her story made complete sense, at least in the context of the facts that we had been able to establish. There had been the footprint on the beach and the second footprint in the dead man’s blood, but the door at the back of the Snuggery had definitely been locked from the inside when we examined it on Sunday morning. Le Mesurier’s body had been saturated in blood, which explained the stain that Hawthorne had found on the back of his phone in the study, and indeed why the phone was there at all. And I had seen Maïssa coming back downstairs when she had made her initial recce, checking where the study was for later.

Even so, it occurred to me that there was a piece missing from the jigsaw. ‘Can I ask something?’ I said. I didn’t want to annoy Hawthorne.

‘Go ahead, mate.’

‘Did either of you drop a coin inside the Snuggery? A two-euro piece?’

When she was pretending to be a poet, Maïssa had treated me with disdain and I hoped it had been part of her performance. But even though she had now been revealed as an undercover investigator, her attitude remained the same. ‘Why would we do that?’ she snapped. ‘Do you think we are idiots?’

I didn’t know how to reply, but for once Hawthorne came to my defence. ‘Actually, I’d say that both of you are fucking idiots, if you want the truth,’ he began. ‘You come over here like Batman and Robin and you get yourselves involved in a murder investigation. But you don’t help anyone because you’ve got bigger fish to fry. In fact, you were obstructive. You say you made no difference to the crime scene, but that’s not true. You took the mobile phone even though it was covered in blood and you left it in the office. You opened and you locked a door. You didn’t even report the crime! You let him sit there all bloody night while the trail went cold. Who knows – but for your meddling, Mrs le Mesurier might be alive right now. You left her to find her husband’s body, but if we could have got there sooner, if we could have questioned her before she’d had time to think, she might have told us what she knew.