He had her there.

‘No, I know. I don’t know.’ She stopped to laugh at herself, unsure why she had; it didn’t belong here. ‘Obviously that can’t be a coincidence. Maybe someone wants me to think I’m being stalked by the DT Killer.’

‘Why would someone want that?’

‘Ravi, I don’t know.’ She felt defensive all of a sudden, hot, the fence going up again, but this time to keep Ravi out. ‘Maybe someone wants to drive me crazy. Push me over the edge.’

They wouldn’t have to push very hard at all. She’d walked herself right up to the edge, toes hanging over the drop. One sharp breath to the back of her neck would probably do it. Just one question between her and that long fall down: who will look for you when you’re the one who disappears?

‘And no one has been killed since this Billy guy was arrested?’ Ravi double-checked.

‘No,’ Pip said. ‘And it’s a very distinctive MO, the duct tape around the face.’

‘Budge over a sec,’ Ravi said, rolling her chair away from the desk, her hands falling from the laptop.

‘Hey.’

‘I’m just seeing something,’ he said, kneeling down in front of the screen. He flicked to the top of the page, deleted the current search items and typed in Billy Karras Innocent?

Pip sighed, watching him scroll quickly through the results. ‘Ravi. He confessed and he pleaded guilty. The DT Killer is behind bars, not outside my house.’

There was a crackling sound in Ravi’s throat, somewhere between a gasp and a cough. ‘There’s a Facebook page,’ he said.

‘For what?’ Pip dug in her heels to scoot the chair back.

‘A page called Billy Karras Is Innocent.’ He clicked on it, and Billy Karras’ mugshot filled the screen as the banner image. His face looked softer the second time, somehow. Younger.

‘Well, of course there is,’ Pip said, pulling up at Ravi’s side. ‘I bet there’s a Facebook page proclaiming the innocence of every single serial killer. I’d bet there’s even one for Ted Bundy.’

Ravi hovered the arrow above the About tab, pressed his thumb into the trackpad to bring it up. ‘Oh shit,’ he said, scanning the page. ‘It’s run by his mum. Look. Maria Karras.’

‘Poor woman,’ Pip said quietly.

‘On 18th May 2012, after sitting in a police interview room for nine hours without a break, my son gave a false confession to crimes he did not commit, a confession coerced by intense – and illegal – police interrogation tactics,’ Ravi read from the screen. ‘He immediately recanted the next morning, after some sleep, but it was already too late. The police had what they needed.’

‘A false confession?’ Pip said, looking into Billy Karras’ eyes, as though the question were for him. No, it couldn’t be. Those were the eyes of the DT Killer staring back at her... they had to be. Otherwise –

‘Serious systemic failings in our criminal justice system...’ Ravi started skipping, on to the next paragraph. ‘Need three thousand signatures on the petition to local MP, oh man, she only has twenty-nine signatures so far... trying to bring Billy’s case to the attention of the Innocence Project so we can appeal the conviction...’ He stopped. ‘Oh look, she’s even put her phone number in the contact info section. Please contact me if you have any legal experience or media connections and think you can help me with Billy’s case, or would like to help collect signatures. Please note: prank callers will be reported to the police.’ He turned from the screen, locked eyes with Pip.

‘What?’ she said, reading the answer in the downturn of his mouth. ‘Well, of course she thinks he’s innocent. She’s his mum. That’s not proof.’

‘But it’s a question mark,’ he said firmly, dragging Pip and the chair closer. ‘You should call her. Talk to her. See what her reasons are.’

Pip shook her head. ‘I don’t want to disturb her. Give her false hope for no reason. She’s clearly been through enough.’

‘Yeah.’ Ravi ran his hand up her leg. ‘The very same thing my mum went through, that I went through, when everyone thought Sal killed Andie Bell. And how did that come to an end again?’ he said, tapping a finger to his chin while he pretended to grapple for the memory. ‘Oh yeah, with an unsolicited knock at the door from an overly persistent Pippus Maximus.’

‘That was entirely different,’ she said, turning away from him, because she knew if she looked at him any longer, he’d convince her to do it. And she couldn’t do it. Could not.

Because if she called that poor woman, that would be admitting there was a chance. A possibility. That the wrong man was sitting in prison. And the right man? He was outside her house, drawing headless stick figures of the women he’d already killed, coming for her, beckoning her to join them. Number six. And that would be a game she wasn’t ready for. A stalker was one thing, but this...

‘OK, never mind,’ Ravi shrugged. ‘How about we sit here twiddling our thumbs instead, just wait and see how this whole stalker thing pans out? The passive approach. Never thought I’d see you opt for a passive anything but we’ll just hang tight, kick back. No biggie.’

‘I didn’t say that.’ She rolled her eyes at him.

‘But what you did just say,’ he said, ‘was that this was for you, that you can do this alone. This is what you are good at, investigating.’

He was right, she had just said that. Her test. Her trial. Her final judgement. Save herself to save herself. That was all still true. Even more so if there was that chance, that possibility, that there was a right man and a wrong man.

‘I know,’ she said quietly, conceding with a long outward breath. She’d known as soon as she’d finished reading the article what she had to do, had only needed Ravi to draw it out.

‘So...’ He smiled the little smile that always got her and dropped her phone into her hand. ‘Investigate it.’

Pip had stared at the numbers so long they were burned into the underside of her eyes. 01632 725 288. A lilting tune inside her head that she could now repeat back, without looking. An ever-repeating loop that had played through her head all night as she’d begged for sleep. Down to her last four pills now.

Her thumb hovered over the green call button again. She and Ravi had tried it five times yesterday, but it rang out each time, no voicemail. It was a landline and Maria Karras must have been away from home. Maybe even visiting her son, they’d guessed. Pip said she would try again in the morning, but now she was stalling, afraid even. Because once she pressed that button, and Maria picked up on the other end, there’d be no going back. No un-knowing what she knew, or unhearing or unthinking it. But already the idea had burrowed deep, settling down inside her head next to Stanley’s dead eyes and Charlie’s grey gun. And even now, as she clicked a ballpoint pen in one hand, she heard something in the click and unclick. Two distinct notes, two letters. DT. DT. DT. And yet, she kept on clicking.

Her hand was resting against her notebook, a new page, beyond her notes on body decomposition and livor mortis. Maria Karras’ number scribbled there. She couldn’t escape it.