‘Then who? Who sent it? Tell me or I’ll ring the police.’ It’s an idle threat but Jake doesn’t know that. I can’t ring the police, not until I’ve checked whether the knife is one of mine.

Jake looks across at the photograph of Billy on the mantelpiece. ‘It’s from a girl.’

‘What girl?’

‘A girl I know.’

‘You haven’t left the house in days. How could you have met a girl?’

‘Well, I …’ He rubs his palms against his thighs. ‘I haven’t exactly met her in person yet but … but I know her.’

‘How?’

‘Through –’ he clears his throat – ‘Tinder.’

‘Tinder? The dating app?’

‘Yeah.’

‘But what about Kira? I thought you loved her.’

‘I do. I do love her, more than anything in the world, but she won’t let me near her. We haven’t had sex in months.’ The base of his throat flushes red as he stares at the carpet. ‘I was just having a bit of fun, a bit of banter.’

I hold out a hand. ‘Show me the phone.’

‘No.’

‘Show me the phone, Jake.’

‘Mum, it’s … the messages, they’re … they’re quite explicit.’

‘Show me the phone.’

‘Okay. But you’re not going to like it.’ It seems to take an age for him to cross the living room and join me on the sofa. He tilts the phone away from me and unlocks it, then shows me the screen. ‘See, Tinder.’

He points at a white icon containing a red flame. It’s the same app Liz showed me earlier.

‘Show me the messages.’

He cringes away. ‘Mum, please.’

‘Now, Jake.’

‘Okay.’ He sighs as he taps the message icon and a list of his most recent messages fills the screen. The one at the top says:

I can keep a secret if you can.

It’s the message I saw earlier. Below it is a message Jake sent:

I shouldn’t be doing this. I’m really nervous someone will find out.

The one before that reads:

I can’t wait to see you. Last night I fell asleep dreaming of your cock in my mouth and your fingers in my hair.

Beneath it, another message from Jake:

I really want you. I know I shouldn’t but you’re all I can think about. You make me feel things I haven’t felt before. I want to fuck you really hard and—

‘Okay.’ I push the phone away. ‘I’ve read enough.’

‘I told you.’ Jake can’t bring himself to look me in the eye. ‘I told you it was bad.’

‘Bad?’ Rage builds in my chest as I think of Kira, standing at the back door crying because of how much she loves him. ‘Go!’ I point at the living-room door. ‘Get out of my sight before I do something I regret.’

Chapter 37