In the daylight, the Snuggery presented itself as a grey cement box about the size of a single-car garage with metal doors that swung open like shutters and a modern glass door behind. There was a flat roof that doubled as a viewing platform, with three narrow windows just below. A flight of concrete steps climbed steeply up the side. The whole thing was enclosed by shrubs and wild flowers, as if it was trying to hide away from the modern world. It was some distance from the main house: with the party in full swing and the jazz band playing, it would have been quite possible for Charles le Mesurier to cry out without being heard.

The metal doors had been pulled back and the glass door was half open too. Colin Matheson stayed where he was, not wanting to go back in, so Hawthorne continued without him, accompanied by Dr Queripel. I hesitated for a moment too. Then I went in.

From gunnery to snuggery: there was something distasteful about the change of use. Originally built for killing Allied seamen, the concrete box had been turned into something like a Turkish harem, the walls concealed behind heavy velvet curtains, with a thick Persian rug and an ornate coffee table surrounded by cushions on the floor. The curtains on the back wall had been pulled to one side, revealing a second set of metal doors, identical to the ones through which we had entered. It might have been possible to come in this way, climbing up from the beach, but they were bolted from the inside.

Two low leather banquettes with an arrangement of dark-coloured cushions had been set against the long walls, facing each other, and an elaborate light hung from the ceiling, the wooden shade perforated with tiny triangles, circles and crescent moons. An equally exotic drinks cabinet stood to one side, one door open to reveal a selection of glasses and bottles on mirrored shelves. All that was missing was the hookah and the belly dancers.

Charles le Mesurier was sitting in a high-backed wooden chair – actually it was more like a throne – facing the garden, with his back to the second door. I’ve described many deaths in the course of my work, in books and on TV, but I’m not sure I’ve ever managed to capture the absolute horror of the real thing. It’s the smell that hits you first, sickening and unmistakable. Dead actors look nothing like dead people. Once the blood has settled and life has drained away, the human body doesn’t look remotely human. Knife wounds are particularly disgusting. And I write about these things for entertainment! Sometimes I wonder what I’m doing.