Still shaken, Nina got in the back and for a moment had to concentrate on remaining calm. She would never understand how Claire had managed to keep such an awful secret all these years. Nina shuddered. John Moore must have been blackmailing Claire in some way. It was the only explanation; her mother would hardly have chosen to act like that. What a swine the man had been. Claire had probably – no, she had definitely acted against the law in saying nothing. Imagine if she was still alive – she could have ended up facing charges. Child pornography was a bit different to stealing petty cash or cooking the books.

And – dear God in heaven – had any child suffered abuse because Claire hadn’t reported John Moore? That was something they would know by the end of the investigation and the answer was going to be ‘yes’. And Claire must have known that. Bile rose in Nina’s throat and she swallowed, feeling it burn all the way to her stomach. How terrible… Claire’s silence had condemned who knows how many kids to vile abuse. And her mother had lived with this knowledge…

Naomi turned from the front seat and pouted at her. ‘Mum! I wanted to - ’

‘They’re looking for evidence of the illegal business, Naomi.’ Nina gave herself a mental shake. She couldn’t think about the ramifications of Claire’s silence now, with Naomi upset and waiting for an answer. The truth and nothing but the truth, but not quite the whole truth, that was what she needed here. ‘And of course anything that would lead them to the blackmailer. We don’t know who that could be. And Sam was right to take you to the car. Things like this aren’t suitable for children to hear about.’

Naomi scowled at Sam, then turned back to Nina. ‘I bet I can understand. What kind of illegal business is it?’

Nina struggled for words. Not the whole truth indeed. ‘I don’t know exactly, Naomi, and I don’t really want to know either. I’m afraid John Moore wasn’t a very nice person.’

Naomi was silent, and Nina slumped in her seat. How much did Naomi know about paedophilia? ‘Stranger danger’ had been a theme in their lives, of course, but Nina had never seriously considered they would come into contact with a paedophile. No one did. But the day when she would have to explain more about John Moore’s ‘illegal activities’ was coming, nothing was more sure than that. She should start getting her ideas together about how best to phrase things so that a ten-year-old would understand without losing her faith in the entire human race. Not an easy task.

The Riverside Water Party, set up by a trio of small lakes in the country park, was lively and crowded, with competitions for children and displays of aquatic sports and other activities. Naomi was fascinated by the water rescue dogs, several of which were enormous Newfoundlanders, and for a long time refused to be tempted away from their stand by the lakeside. Nina and Sam left her to it and settled down under a tree a short distance away where they could keep an eye on her.

‘I hope I didn’t stand too hard on the poor kid’s toes back there,’ said Sam, passing Nina a smoked salmon sandwich. ‘She was none too chuffed when I insisted on leaving you alone to talk to the police.’

‘I’m glad you did,’ said Nina fervently. ‘I have no idea how best to explain all this to her. Don’t worry, Sam, she’ll come round. She hasn’t got over her Grandma’s death yet, and losing part of her trekking holiday isn’t helping.’

To her dismay, however, Nina saw that her daughter was still very miffed with poor Sam. Naomi came back for something to eat with a sullen expression on her face.

‘Mum, can I go and buy an ice cream? I don’t like fish,’ she said, turning her nose up at Sam’s cool box. ‘Or chocolate yoghurt.’

Nina pulled out her purse, refraining from pointing out that both appeared regularly on the table at home and Naomi had yet to voice an objection. If only peace of mind was as easily purchased as ice cream. She would part with any amount of John Moore’s fortune if she could buy something to help Naomi through what had turned into the worst summer of both their lives.

She watched unhappily as the girl trailed over to the ice cream van and back, demonstratively giving Sam a wide berth. As soon as she’d handed over the change she was off again back to the dogs.

‘Don’t worry,’ said Sam, as they packed up the picnic. ‘I know it’s not personal.’

He was right, thought Nina. But she could have done without yet another complication. Sam was the closest thing she had to a friend down here, and now Naomi had taken a scunner to him, as Grandma Lily would have said.

The party continued with music and dancing, and it was after ten when Sam pulled up outside John Moore’s house, Naomi half-drowsing in the back. Nina undid her seat belt. Had the police found anything? Heavens, she had butterflies in her tummy about it – they might have come across something that would change the whole situation. Oh, if only…

She turned to Sam. ‘Want to come in and see what the police have been up to?’

‘You bet,’ he said, pulling the key from the ignition.

Naomi bounded up in the back seat. ‘The police! Are they still here?’

The police were gone and the house was tidy, though Nina saw signs everywhere that things had been disturbed, moved, rummaged through. The smell of old books in the study was almost choking, and Nina wrinkled her nose. They must have flicked through John Moore’s entire collection. It was unnerving, even though this wasn’t her home. Her house, but not her home. And what had all those policemen found in her house?

‘Mum! They’ve left some boxes from the attic in the living room!’ said Naomi, who was wide awake again, running from room to room.

Nina went to look. There was a note from David Mallony on the uppermost of three cardboard boxes on the coffee table.

‘All the ‘good’ photos are here. We’re taking two further boxes to the station for investigation. Those still in the attic contain clothes and china.’

Nina breathed in deeply. It sounded as if the ‘further boxes’ contained pornography. Thank Christ she hadn’t left Naomi to explore the attic by herself the other day.

Sam patted her shoulder. ‘I’ll make coffee, shall I?’ he said. ‘You’ll want to have a look at these.’

Nina opened the smallest box. It was almost full; there were dozens of small, black and white photos, the kind that would be pre-1960.

‘Bo – ring!’ said Naomi theatrically.

‘‘Fraid so,’ said Nina, glad that the girl wasn’t itching to look through the photos. ‘I can sort them out, and show you any that are interesting later, okay? Look, it’s late. Why don’t you scoot off and have a nice bath before you go to bed? You can use my new body lotion.’

To her relief Naomi took the bait and disappeared upstairs. Nina stared round the room, looking for somewhere to lay the photos out to sort through them. The table under the window with its two drop leaves seemed the best bet. She moved the ugly crystal bowl from the table top, and soon created a good-sized surface to work on.

‘I don’t think those black and white ones’ll show anything very interesting,’ she said, putting the small box to one side and accepting a mug of coffee from Sam. ‘My father would be a child in these. What I’d really like to find are photos of my parents together, maybe some of me as well. And anything else with people, too.’

Sam opened the second box. ‘Hm. None of these seem to have a date on them,’ he said, stirring the photos with his index finger. ‘They’re all colour, though, so they’ll be more recent. Why don’t I sort them into those with and without people, and you can arrange the people ones?’

Twenty minutes work was enough to convince Nina she had a mammoth task on her hands. Surely most families didn’t have half as many snaps as this; one of her relations must have been an enthusiastic amateur photographer. She found several photos of John Moore, but none of her mother or herself, though there were several dozen with strangers. Some included the woman and the little boy who were on the photos Sam had found in the desk, but there was no way to tell who anyone was. Not one of the photos had names or dates on them, and there must be dozens still in the box. Who on earth had taken them all?