‘No, you wouldn’t need to do all that, Dad. You’d just have to put it into reverse image search.’

Of course.

‘Except we don’t have any photos of Fiona.’

‘Rose might.’

I immediately headed upstairs to Rose’s room, with Dylan following. Rose might have her phone with her, but her laptop, which she used mostly for homework or to play Roblox, automatically synced with her phone, so all her photos would be on there.

‘Do you know the password?’ I asked.

‘It always used to be Lola123. Capital L.’ Dylan had helped her set the laptop up when she’d first got it. ‘I told her to change it to something harder to guess, but don’t know if she did.’

I tried it and thanked the gods Rose had never got round to updating it. I was in, and navigated straight to her photos app.

There were very few photos taken in the last few months. Ninety per cent of them were of the dog – which, to be honest, wasn’t dissimilar to my own photo reel. A few landscape pictures she’d taken on holiday. My eyes were immediately drawn to somepictures taken at what I recognised as the Horniman Museum. Dog and wolf heads mounted on a wall. A gigantic stuffed walrus. There were some pictures of Rose taken on this trip. A few of her in a park too.

But no photos of Fiona.

‘Fiona must have some photos of herself,’ Dylan said. ‘In her house, I mean.’

I looked towards the wall. Fiona’s house was on the other side. If only I could walk through it.

‘I can’t break in to her house,’ I said. There was nothing else for it. I was going to have to talk to the police.

‘We don’t have to,’ Dylan said.

‘Go to the police?’ I was losing track of what I’d merely thought and what I’d said aloud.

‘No, Dad.’ My fifteen-year-old son was looking at me like he was worried I’d lost my mind. ‘Break into her house.’

He went over to Rose’s bedside drawer, opened it and rifled around inside. I was about to say something about his sister’s privacy when he turned around, proudly brandishing a key. ‘Rose told me Fiona gave her a key so she could go in and feed the cat when Fiona was away that time.’

‘Of course.’

We headed downstairs. Leaving the house, I heard Tommy’s voice in my head again, calling Fiona a psycho. I braced myself, terrified of what we might find next door. Increasingly scared that I was going to find something in there that would prove Dylan was right.

That not only did we live next door to a psychopath, but that my daughter was one too.

34

Fiona’s place was the kind of neat and clean you could only achieve if you didn’t have children. A house where you could leave a room tidy knowing that next time you walked back in that room it wasn’t going to have been trashed.

Dylan and I had let ourselves in through the front door, and the kitten had immediately come running up to us, meowing and rubbing around our ankles. The cat’s presence gave me some comfort. Surely Fiona wouldn’t leave it on its own for too long? She genuinely seemed to like animals, which was one of the reasons I found it hard to believe she was a psychotic killer. Didn’t most serial killers start off by torturing animals? Maybe that was just a pop-cultural belief.

Or perhaps she had only acquired Karma the kitten to lure Rose into her house. Maybe when there was no one around, she mistreated this poor animal.

‘Rose genuinely loves cats and dogs,’ I said.

‘And that means she can’t be a bad person?’ said Dylan. Again, I hadn’t realised I’d spoken aloud. ‘Keira told me it’s a myth that dark triad people can’t like animals. Harold Shipman used to cry over dogs that were being used for medical experiments. Dennis Nilsen loved his border collie. Even Ian Brady liked pets, and askedfor the proceeds of his memoir to be split between several animal charities if it was ever published.’

‘How do you know all this stuff?’

‘Keira.’ Of course. ‘She wants to be a psychologist like her mum, but specialising in the criminally insane.’

‘Why would she want to do that?’

He shrugged. ‘It’s interesting. Even you find that stuff fascinating. I remember you going on about how Charles Manson was influenced by the Beatles.’