‘You’re joking.’ Sellers laughed, but not for long. ‘You’re not joking? Fucking hell.’

‘“Sexist Pig Detective In Woman-Has-Non-Compliant-Thoughts Shocker”,’ Halliday muttered.

‘Like you said: we don’t need to agree. I came here today to ask you – politely – to please stop writing, publishing, blogging about Billy and these murders. You’re muddying the waters, and making it harder for us to control what’s out there. That could lead to us taking longer to catch him, which in turn could lead to more deaths. Of women, perhaps,’ Sellers added.

Halliday was nodding. She couldn’t be about to announce her intention to cooperate, could she? It seemed impossible. ‘How very familiar all this sounds, even though we’ve never had this conversation before,’ she said.

‘What do you mean?’

‘How ultra-reasonable you sound! Who could say no to such a request, when lives are at stake?’

‘You?’

‘Damn fucking right, me. I’ll concede it’s not all your fault – you’ve just come with your individual request and you can’t understand why I wouldn’t submit, shut my feminist mouth, help the good old police who, after all, only want to catch a killer, and, as you point out, that would benefit women – his future victims.’

‘Right. So what’s the problem?’

‘Oh, only that men who believe they’re well meaning, reasonable, enlightened, have been trying to derail every conversation started by women about how to demolish misogyny since time began. They don’t realise that’s what they’re doing – of course not. They always have a great excuse. “Shut up about misogyny because you’ll only make it worse, you’ll make women targets for even more male violence.” “Shut up about misogyny because we’re trying to catch a murderer and you’re interfering with our media message.” Obviously I want Billy Dead Women rotting in a jail cell as soon as possible, but, no, I’m sorry, I won’t be silenced about what’s patently going on here. The misogynistic element won’t disappear from this case if I stop mentioning it. Unless we notice and name the problem, we can’t solve it, and that’s my priority. Just as yours is catching Billy.’

‘It isn’t what’s going on, though.’ Sellers sighed. ‘What if Billy killed two more pairs of best friends and all four victims were men? Would you concede then that you were wrong?’

Halliday tilted her head to the left. She seemed to be considering it. ‘Maybe. Though I predict that won’t happen. He’s started out killing many more women than men for a reason. Mi—’

‘Misogyny.’

Halliday clapped. ‘I suppose you deserve some credit for getting the right answer, even if you don’t really believe it. Look, you asked why I agreed to meet you—’

‘Is misogyny the answer to this question too?’

‘I’m not going to stop writing about Billy, but I might help you catch him.’ Halliday reached inside the bag that was sitting by her feet. Much rummaging and under-breath swearing followed as she failed to find what she was looking for. Sellers hadn’t spotted the slogan on the bag when she’d first arrived; it must have been on the side facing her body. It read: ‘Women who seek to be equal to men lack ambition’.