‘Eh? Oh, in my room. Not really.’

‘Was it too loud for you to be able to hear if someone came in and went up the stairs?’

‘Hmm. Yeah, I guess so.’

‘What about if Frankie had made a noise – started crying or called out?’

‘I would have heard that. I always hear her, even if I have my headphones on.’

Patrick understood that. There was something about the human brain that was designed to pick up children’s cries, although he had always thought it was only one’s own children you could hear.

‘Did you leave your room at all between eight and ten?’

‘No.’

‘Not even to use the toilet?’

She looked at him as if the idea of this middle-aged man asking her about her visits to the loo was the most gross thing she’d ever heard. ‘I’ve got my own bathroom.’

En-suite. Very nice. Patrick scribbled another note. ‘When you left your room at ten and went downstairs to watch TV, did you check in on Frankie?’

She stared at the table. Next to her, Sally scrutinized her carefully. Alice’s tone, when she replied, was defensive. ‘No. I was sure she was asleep. I didn’t fucking expect some fucker to waltz into our house and snatch her, did I? Otherwise I would have camped outside her room with a knife.’

‘Alice, calm down,’ said Sally, who had flinched at Alice’s f-word double whammy.

Patrick adopted his most soothing voice again. ‘We’re not judging you. Alright?’ Although he couldn’t help thinking that this sort of bad language was pretty unusual, from a well-brought-up fifteen-year-old from an upper middle-class family in Teddington.

She nodded, refusing to meet his eye.

‘OK. So, did you see or hear anything unusual at all?’

‘No. Nothing.’

‘Have you seen anybody or anything out of the ordinary near your house recently?’

‘Like what?’

‘Like, for example, people hanging around. Watching the house. Men you don’t recognize.’

She wrapped her arms even more tightly around herself. ‘Oh god, that’s too creepy. No, I haven’t.’

‘Did you have anybody over last night?’

A second’s hesitation, and her eyes flickered briefly up and to the right. ‘No.’

Patrick, who had been acting as casually as he could when he asked her that question, looked up from his notepad and said, ‘Are you sure?’

‘Yeah, of course I’m sure. I’m not senile.’

‘You didn’t have your boyfriend round?’ asked Carmella. ‘Larry?’

‘No! Who told you that?’

Carmella raised her palms. ‘No one. I was just checking. I mean—’ she leaned forward conspiratorially, ‘—I was a teenage girl once. I’d always have friends round if my parents went out.’

Alice sniffed. ‘Well, I didn’t. And I don’t see how any of this could help find Frankie anyway.’

‘We just want to know if there were any other potential witnesses,’ said Patrick. ‘Did you speak to anyone?’