So I became part of Rebecca’s story. A story which she had pre-written and already knew the ending of. She’d been in control the whole time, played me like a guitar. Only Woods wasn’t completely on the money. She hadn’t known all along. My mind keeps drifting back to the night of her arrest in the Greek restaurant, when she’d used my full name. I never recalled telling her it, but she already knew. I google the words ‘Rachel’ ‘motorcycle accident’ and ‘death’. My girl makes the top three: ‘Policeman’s fiancé, 35, killed in motorcycle crash.’ It’s under Touchy’s byline. I blink at the screen.

Rebecca wanted to be caught; and she’d wanted me to catch her once she discovered who I really was. But why? It’s a question that will remain unanswered now, a question she took to the grave with her. Was it like Magnesson said, that Rebecca had completely separate personalities and was literally two different people who she could compartmentalise?

Perhaps she wanted the kind of love that Rachel and I had, and she hoped I would give it to her? I don’t know. Perhaps she had fantasised about leading a normal life, like the one she thought I had, and perhaps she knew she would never get it, but it felt good to pretend. Perhaps she knew deep down that neither of us could ever truly have the lives we both wanted, and she felt a connection with me because of this. I don’t know, but these questions will haunt me for the rest of my life.

Sometimes there is no why.

I’ve been given six weeks paid ‘leave’ due to personal circumstances, which Woods tells me is enough time for him to ‘clean up the bloody mess I’ve left behind’, and smooth things over with the IPCC. He told me to take a holiday and as part of the deal I must undertake some counselling. I’ve done neither yet, but I am thinking of going to LA, maybe stop off in Cambria, go to where I scattered my girl’s ashes one last time.

I pay Janet Baxter a visit and explain that we caught the woman who killed Nigel. I owe her an explanation; I owe her a full stop. I tell her about Rebecca Harper and give her a little background, and then I finally reveal that this woman had taken her own life and died in police custody, that there will be an inquiry, but that I’m truly sorry there will be no trial as a result. I put my hand on hers as I explain, and it feels warm to touch.

I don’t tell her that I had come to know Rebecca or how. Woods has told me to keep this quiet, he said that no one needs to know. He and I are the only two privy to this information. Davis has been silenced. But she’s a good copper is Lucy Davis, loyal to a tee. Woods is going to do a cover-up job. I’d like to think it’s a decision he made to save my bacon – and reputation – but in reality I think it’s more likely to save his annual golf membership and his face. Still, it’s an unprecedented move on his part. I don’t know if I’m grateful or not.

Janet Baxter is relieved when I tell her about baby George and how close he came to meeting the same grizzly end as her Nigel. Even now, with no one to put behind bars for the crime against her husband, she’s shows nothing but compassion. Without malice, she says she’s glad that Rebecca Harper is dead. ‘Perhaps now we can all try and move on.’

I feel a sadness from Janet Baxter that I recognise in myself, a sort of fait accompli, a weary resignation to her situation – and a life without the man she loves. ‘He was a silly old fool,’ she says, ‘but he was my silly old fool.’

And I have to fight back tears as she says it. She thanks me profusely for ‘all your tireless hard work’ and tells me she knew I would never let her down, she’d always had faith in me to get to the bottom of this and find her husband’s killer. I can barely look in her watery eyes. Before I leave I hug Janet and she reciprocates. She smells of freshly washed clothes, of the expensive stuff. ‘Life goes on,’ she says, ‘that’s what’s so sad.’

‘Things will get better, Janet.’ I reply. It’s the last lie I hope I’ll ever have to tell her.

After I leave Janet’s place I drive up to the cemetery near Wandsworth where Karen Walker is now resting and I lay flowers on her small headstone. It takes me almost an hour to find it. Just three people turned up for her send-off – myself one of them – and I think of all the people out there, faceless, nameless people like Karen with no family, their tragic lives unwitnessed, their passing unmissed. There’s a picture, a photograph of her cat, Esmerelda, next to a bunch of dead flowers. I think about throwing them away but I don’t. Whoever left them there, I hope they’ll never forget her, just as I won’t.