Lennon’s reaction was calm, unruffled. He wrote a note in his black notebook, in such small squiggly writing that Helen couldn’t make out what it was. Then he gazed into her eyes again.

‘I didn’t mean anything. Some kids are wanderers, some aren’t. We just need to know that Frankie isn’t.’

‘She’s not,’ said Helen, visualizing Frankie fast asleep in her toddler bed, her cheeks hot and red in slumber, a snail trail of contented drool linking the corner of her mouth to her flannelette sheet, clutching Red Ted under one arm. The pain was like a knife in her stomach; she felt eviscerated by it.

Lennon stood up, walked across to a small table in the corner of the interview room and opened a cardboard folder.

‘When did Frankie draw this?’ he asked, removing a slightly crumpled piece of paper with one of Frankie’s crayoned efforts on it. Helen took it and frowned.

‘I’ve never seen it before.’

‘Really? It was on the desk in her room when we searched it, under a drawing of a cat.’

Helen looked more closely at it, and her hand flew to her mouth when she realized what it was. ‘Someone looking through a window at her? Oh my God!’

‘It might not mean anything sinister,’ Patrick reassured her. ‘Frankie’s bedroom window was still locked – we’re certain no-one came in that way.’

‘What if they put a ladder up, to look in?’

‘Well, there isn’t one there now. It’s probably nothing relevant, but we just need to document everything.’

‘I tidied up her room before we went out. There were definitely no drawings on the table then – she must have done them after her bath. When Alice was meant to be looking after her . . .’

‘What makes you think she wasn’t?’

Helen’s hand shook as she held the drawing. ‘Because Alice loves drawing too. She always helps Frankie with her drawings, adds background, does the bodies around the faces she draws, that sort of thing. They draw maps together too – funny little maps that Frankie calls ‘naps’. She dictates the landmarks and Alice draws them. They look so sweet when they get stuck into an art session, their heads together, tongues sticking out . . . She didn’t really like drawing without Alice there.’

Her voice trailed away.

‘Maybe Larry did come over after all,’ she said eventually.

Lennon looked up from his pad. ‘Larry?’

‘Alice’s boyfriend. She’s not supposed to have him round when we’re not there.’

The detective arched an eyebrow. ‘You don’t approve?’

‘Oh, no, it’s not that. But . . . well, I knew that if he was there Alice would be . . . distracted. When she was supposed to be keeping an eye and ear out for Frankie.’