She is pleading with him and she looks at me and I see desperation in her eyes.

Alex shakes his head, defeated. ‘It would always haunt me. The guilt. It’s already destroying me, Heidi. Whatever happens, I have to tell the police. I’ll not be able to live with myself if I don’t.’

Heidi is crying. Silent tears running in rivulets down her cheeks. They both look so broken and I think of the little baby upstairs, the baby who curled her hand around my fingers not that long ago. Who trusted me to rock her back and forth. Those big, innocent eyes that had looked at me with such trust. And I realise that no one is really guilty here at all. Except for Joe.

And Joe, now dead and buried, holds the key to all this.

‘It was his diary that I was looking for,’ I interject. ‘The one Alex saw. It will help back up Alex’s story, won’t it? It’s not where I left it, but it has to be here somewhere. We just have to keep looking.’

‘Then we’ll do just that, we’ll keep looking,’ Heidi says, squeezing Alex’s hands tightly.

She stands up and starts sorting through the drawers in the sideboard in the living room – pulling out old paperwork and shuffling through it. My father was nothing if not fastidious about keeping his affairs in order and it soon becomes obvious there’s no diary of any kind hidden in the back of a drawer or under mounds of old bank statements.

I look in the drawer of the console table in the hall. Again, there is nothing of note. It’s neat and organised. A book of stamps. Some pens held together with an elastic band. A packet of envelopes and a small address book, in which Dad had painstakingly written the names of his friends and colleagues in block capitals and always in black ink.

We both go together into the bedroom. I double-check the wardrobe, as does Heidi.

‘It was there,’ she says, pointing to the far left corner of the wardrobe, which is now just an empty shelf. ‘That is where you put it. Remember?’

‘Yes, but I looked and it’s definitely not there any more.’

She pulls aside the rail of pressed shirts and trousers and looks down at the floor of the wardrobe. ‘They’re all gone,’ she says, looking up at me.

‘All what?’

‘All his diaries and notebooks. He kept them there, in shoeboxes. A diary for every year. There were at least twenty of them here.’

‘Would the police have taken them?’ I ask. ‘Those SOCO guys were quite thorough. It’s the only logical explanation.’

It strikes me that Heidi was able to open the wardrobe door without using a key – a key I knew I had. I run my finger to the lock, noticing that it has been broken.

‘Someone’s been in here. They used force,’ I tell her, pointing to the door.

‘Would the police have busted a lock? They left everything else just as it was,’ Heidi says.