Then there are another twenty-five friend requests. People who think they know the imaginary Monica. I wonder if that’s worth a psychological study as I slip back into serious day mode, then I focus on the task in hand. I push the flash drive into the USB and flick through the photos until I find the one. You’re in her room at the Ibis. I stare into the background. It’s exactly as I remember it. A spike of temper rises but I push it down, down into the depths.

Select. ‘What’s on your mind?’ Facebook asks me. I’ll tell you what’s on my mind, Facebook. Revenge. I type: ‘#ThrowbackThursday #London #Backintheday’. I’ve already saved some pictures of made-up Monica to her photos, and I post some more of her in London just to make it look like these are just part of a series of pictures of Monica’s past. Only three people will know the truth. Christine will know. I’ll know. And you, Jack. You’ll know.

You know me, Jack.

Chapter Six

I arrive at work early, and I log into my own Facebook account on my office computer. More people have friended the lovely made-up Monica and I flick through the profiles of people who I haven’t seen for more than fifteen years. Then back to the picture. It’s there, sitting in the middle of my screen. You’re laughing. Jack and Christine. It’s obvious from the series of pictures you stuck in the journal that they’re taken using a camera’s timer.

Jack and Christine, laughing at first, then undressing each other. Then naked. Then fucking. But to anyone looking at this single picture, it just looks like Monica was with them in their hotel room, perhaps getting ready for a night out. She took the picture of them together.

I check the ‘number of views’ digit and it’s moving upwards, ever upwards. The picture’s been shared three times. Simone Lawrie, one of your sister’s friends from school, has posted a question mark in the comments section and your name so you are sure to see it.

My mobile phone rings and it makes me jump. I snap out of this fantasy world and see that it’s DS Percy.

‘Hi. Caroline Atkinson speaking.’

There’s a slight pause. I know she’s assessing my opening. But I’m calm as can be.

‘DS Percy. Look, Caroline – if it’s OK to call you Caroline?’

Of course it is. Be as personal as you like.

‘Sure.’

‘OK. Mr Atkinson has been in touch. He’s made a further accusation. About a picture on Facebook.’

I intentionally wait.

‘Oh. Go on.’

‘Well, that’s it. He feels that you have posted a picture from his personal journal, which was in the bag that he claims was left at your house, on Facebook.’