‘As near as you can remember.’

McLaughlin shut his eyes, supposedly recreating the image of that day, which was all part of the cognitive handbook. Eventually he said, ‘I was sitting on the hill in front of the Catholic primary school.’

‘Why there?’

His eyes still shut, McLaughlin continued, ‘It was where we hung out. You could see all up and down the street and onto the houses opposite.’

He went on, ‘I was sitting there watching all the kids coming down the road from the chapel. Two by two, girls in white dresses and veils. Boys in suits. They were heading for the school. Mary McIntyre’s mum came into the garden to watch for Mary. But Mary wasn’t among them. When she couldn’t see her, Mrs McIntyre ran up to the teacher who was at the front. Then they both looked through all the kids. There must have been eighty of them. But Mary wasn’t there.’

He paused for a moment, focusing his now-open eyes directly on Janice.

‘That’s when I saw Karen Marshall, Mary’s pal. She lived in the house opposite the entrance to the school. She was in the front garden. I thought she was waiting for Mary too. But Mary never came. That’s when I knew she was missing.’

‘Tell us about Karen,’ McNab said.

‘Her dad was like you, a police officer. A detective constable.’ He eyed McNab. ‘Better not screw up again, Detective Sergeant, or you’ll be back at that rank.’ He smiled at his own little joke.

McNab felt Janice’s slight nudge under the table, warning him not to rise to the bait. He didn’t, mainly because he was having a mental picture of doing a lot worse than that to the creepy bastard.

‘What happened next?’ Janice asked.

‘Well, things got a bit heated. Mary’s dad arrived. He was a mean bastard at the best of times. Had a big thick belt with a buckle that hung on a hook in the kitchen. He would whistle his kids in for the night and if they didn’t come right away, they got that belt.’

He paused, looking for a reaction. When there was none, he went on, warming again to his story. ‘Mary’s dad went off up the road towards the chapel to look for Mary and the rest of the kids went into the school. Karen came out of the garden and set off to where she and Mary had a den they’d made. They thought no one knew about it, but we all did.’

‘Where was this den?’ McNab said, revealing the map they’d prepared of the area in 1975.

McLaughlin drew it towards him and, after studying it with interest, pointed to a wooded area which lay beyond the open ground between the two schools.

‘You said we all knew about it,’ Janice said. ‘Who’s we?’

‘Me, Mary’s brother Robbie. He used to go up there with one of his pals. What they were up to, who knows?’ He smiled as though he knew exactly.