When I’m out of the shower I grab my scrapbook and take it to my bedroom. Relieved to be lying on my own bed again, I let the book fall open at the first page. Mum and I started it when I was ten. Its first entry is a newspaper clipping of the islanders protesting against the proposed development of a boutique hotel. There’s a picture of us all gathered together in solidarity – Mum and Annie at the front of the group. Annie Webb and Maria Harvey lead protest to keep island a sanctuary, the headline reads. I had proudly cut out the article and pasted it into the book.

I flick to the last page, an entry made on 3 August 1993. I remember the day clearly. It was burning hot, I had stripped down to my swimming costume and was standing under a sprinkler in the garden when Mum came out and turned off the tap.

‘We need to save water. Let’s play something,’ she’d suggested. ‘How about the alphabet game?’

This meant taking turns to find something on the island that started with a particular letter. I had stuck in various things we’d found and had written up others like the caterpillar I’d spotted crawling up a tree.

Now I rub my fingers gently over a daisy and a feather stuck side by side in my book, both long ago turned brown and limp. The list stops at M. I don’t recall if we finished it or not. I can’t even remember how the day ended.

I flick through the pages one at a time, poring over them, searching for clues I know don’t exist, and eventually toss the book across the bed, letting out a scream. Rolling on to my side I thump my clenched fists against the pillow, burying my head in it, grabbing handfuls of white cotton until I can’t squeeze any tighter. Pain and frustration rip through me.

This is my family. These are the people I’m supposed to trust most.

But I no longer trust any of them.

The interview suite in Dorset is in a room at the back of a house. High ceilings and intricate coving are the only interesting features in what is otherwise a blank canvas. The walls are magnolia, bare apart from a digital clock that flashes bright red, and two cameras pointing towards each of the sofas.

‘You’re here as a witness,’ Harwood tells me once he has pointed out that the interview is being videoed. ‘You’re free to leave whenever you want. But as we explained to you earlier, your brother is under arrest for murder.’ I nod as he goes on, ‘There will be times when this may be frustrating for you, but this is a one-way interview. If you have questions we’ll never lie to you but there may be times when we won’t be able to give you information.’