He had sat upright. ‘What?’

‘It’s cute. I like it.’

He had immediately got up and run over to the mirror, trying to see the bald spot. He loved his hair, so much so that when he’d left his ex-wife her final words to him were, ‘I wish you baldness.’ Now it looked as if the witch’s curse was coming true.

He hadn’t been able to perform after Francesca’s words. She’d tried to get him back in the mood before eventually leaving in a huff. Winkler had found a hand mirror and located the offending patch. His dad was as bald as Kojak, but Winkler Junior had always believed that he took after his mum’s side of the family: hirsute and manly. But this was it. The beginning of the end. He spent the rest of the evening looking up hair re-growth products on Google.

So he was in a foul mood this morning. And Mervyn Hammond was going to take the full brunt of his bad temper if he wasn’t one hundred per fucking cent cooperative. Over the past twenty-four hours, Winkler had become increasingly convinced that Hammond was, if not the killer, definitely involved. He had the access to the young fans and would easily be able to persuade them to meet with him by making promises these desperate girls wouldn’t be able to resist. He had, Winkler knew, paid off a young girl who’d been molested by Shawn Barrett, which made Winkler wonder if this Irish girl hadn’t told them everything – if Mervyn’s involvement went beyond bribery and corruption.

There was the signed photograph of Mervyn among Nancy Marr’s belongings – the only connection between the old woman and OnTarget anyone had been able to find. Finally, there was Hammond’s mysterious after-dark visit to the children’s home in Isleworth. Hammond liked young girls. Winkler’s guess was that Hammond had molested Rose and Jessica, and they had threatened to expose him. Or perhaps he hadn’t done anything to them directly but they had found out about him. Hammond was so furious that before killing them he had tortured them.

He pressed the buzzer by the gates and a female voice came smoothly through the intercom. A housekeeper or PA, Winkler guessed.

‘Police,’ he said firmly. ‘I need to have a word with Mr Hammond.’

After a long pause, there was a beep and the double gate swung slowly open. Winkler decided to leave his car out there and walked through, finding himself on a path that led through an immaculately landscaped garden, cone-shaped little pine trees and everything, up to a grand house – one of those Huf houses that were popping up around Surrey. Ridiculous – a house that came in kit form and still cost a couple of mill? It was impressive, though, he had to admit, with its glass frontage and chalet roof.

He passed a kidney-shaped pond, gold and white koi darting beneath the surface, and considered propelling a juicy globule of phlegm into the water. He was so going to enjoy taking Mervyn Hammond down.

Winkler reached the house, walking past a white van parked close to the entrance, to find a middle-aged Asian woman in a white apron – yep, the housekeeper – standing in the doorway. Several black bin bags lay at her feet. He flashed his badge at her.

‘Mr Hammond in his shed,’ she said. Not long off the boat, this one, Winkler thought. ‘I call him and he say please go there.’

She pointed towards a large brick building across the garden. A shed! It was bigger than the house Winkler grew up in; it was in fact a converted barn, by the look of it. Winkler was about to walk towards it when he had a thought.

‘How long have you worked for Mr Hammond?’ he asked, using his most authoritative police voice, wanting her to believe she’d be in trouble if she didn’t cooperate. If she didn’t answer, he might have to use the magic word: immigration. That always worked.

The woman, whom Winkler was pretty sure was Thai, shuffled so half her body was concealed behind the door. Frightened. Maybe Hammond threatened her. Beat her. Don’t worry, Winkler wanted to say. I’m here to take the bad man away.

‘Two year,’ the housekeeper replied.

‘Is he a good man to work for?’

She nodded vigorously. Too vigorously.

‘I bet he has lots of parties, eh? Lots of clearing up for you to do.’

She nodded again, smiling tentatively. ‘Yes, many party.’

‘Famous people, yes? Celebrities?’

The housekeeper’s eyes darted about like the koi had done. She leaned forwards, her eyes like saucers, voice dropping to an awestruck whisper. ‘Yes. I meet Harry Potter.’

‘Really? Nice kid. Any other . . . kids come here?’

The woman cocked her head.

‘You know, like, young girls. Teenage girls.’

She grinned again and nodded enthusiastically. ‘Yes, yes, many young girl. Pretty girls.’

Ibet, Winkler thought. He caught movement behind the housekeeper – a woman dragging a vacuum cleaner across the hallway – and took a second look at the bin bags.

‘Was there a party here last night?’

‘Yes. Big party! We clean up now. Many people sick from drink.’

He tried to get a better look, but she moved her body to block his view.

‘Who was here? Anyone exciting?’

She opened her mouth to answer, then appeared to change her mind, probably realising she’d already said too much. Possibly because he hadn’t been able to control his face when she said ‘pretty girls’. He decided not to push it.

He nodded at the woman and said, ‘Thanks. You’ve been very helpful.’

She wore a bemused expression as he strode off across the damp grass towards the ‘shed’. It was raining even more heavily now and by the time he got there water was dripping into his eyes. He was thankful he’d had the good sense to slip the signed photo, which was tucked inside his coat, into a laminate sleeve. He banged on the door.

‘Come in.’

Winkler wasn’t sure what he expected to find inside the converted barn, but he’d have been less surprised if he’d found a dozen bodies hanging from the rafters.

The entire space was filled with model trains. Not just trains: an entire landscape, with rolling hills and valleys, bridges and tunnels; miniature houses and churches; tiny plastic sheep grazing in a field; people the size of thumbnails waving from a station. And, gliding on tracks around this landscape, replica steam trains, gleaming black and green engines hauling cargo and passengers, round and round, pausing at signals before emitting a whistle and chugging away again.

Mervyn Hammond stood at a control deck on the far side of this display, his mop of black hair falling into his face as he fiddled with levers and rotated dials. He glanced up as Winkler approached but didn’t stop playing with his giant train set.

Winkler noted that Hammond didn’t seem surprised to see him.

‘Mr Hammond,’ he said. ‘I want to ask you about—’

‘Magnificent, isn’t it?’ Hammond said. ‘You know, when I was a kid my granddad used to take me to the station at Crewe to watch the trains. I used to dream of being a train driver. That was all I wanted to do.’ He chuckled to himself. ‘My granddad would turn in his grave if he knew what I do these days. But he could barely afford to buy me a single wooden engine to play with. If he saw this . . .’ He stretched out his arms to indicate his miniature kingdom and Winkler was rendered speechless.

But he thought to himself: train sets. Toys. What does he do, use this to lure kids to his house? Is he into boys too? His paedo radar wasn’t just tingling now, it was going berserk.

Hammond stepped away from the control panel, the fervour in his eyes dimming a little. ‘How can I help you? Detective . . . ?’

‘DI Adrian Winkler.’

‘A colleague of DI Lennon’s? Don’t tell me he’s sent you to ask more questions about Shawn Barrett?’

Winkler shook his head. Beside him, an engine whizzed by dragging half a dozen passenger carriages behind it. The constant circular motion of the toys was making him feel queasy. And there was a cold, squelching sensation in his left shoe. I’m going to get sodding flu, he thought. And it was all this creep’s fault.