‘Great. Let’s try to keep a tight lid on this latest development,’ James said. ‘I know there’ll be lots of pressure because the discovery of the baby’s remains has put the story right back at the top of the news agenda, but if they get a sniff of this then things will get out of control again and we don’t need it.’

There was nothing new to report on the other suspects since none of them had changed their stories and no evidence had come to light to suggest any of them had lied.

Just before James called time on the briefing DS Stevens – joining the meeting via speakerphone – offered a final update.

‘I’ve found something interesting in Nash’s office filing cabinet,’ he said. ‘There are about thirty folders with the names of people and companies his firm has done work for. One is marked Oaktree Farm.’

‘How far back do they go?’ James asked.

‘Quite a few years before Nash took over the business from his father. And here’s the thing. It turns out it was Nash’s father who replaced the interior door to the cellar with the plasterboard wall. The work was actually carried out sixteen years ago.’

‘Then Nash lied to us.’

‘He did, but there’s more. There’s also a receipt for work done eighteen months ago. Nash was called out to put up shelving units in the cellar and to repair the cellar’s external door. Then weeks later Robert Bateman got him to paper the internal wall below the stairs. And get this – Nash was the one who supplied the raindrop paper that makes it hard to spot the peephole from the inside.’

‘This would appear to be another mystery solved,’ James said. ‘It seems obvious to me that he used the opportunity to insert the peephole in the wall. He would have made sure to position it so that it couldn’t easily be seen by the family. At the time he was dating Charlotte so it was a way of keeping an eye on her when she wasn’t with him. He must have had his own keys cut so that he could access the cellar and the space behind the wall whenever he felt the need.’

‘But surely it can’t have been that easy,’ someone said. ‘Wouldn’t the family have known when he turned up at the farm?’

James shook his head. ‘He could easily have reached the exterior door undetected. He owns a motor scooter and he could have left it in a nearby field and then approached the house on foot. Once inside the cellar he could have stayed for hours without being detected. It’s likely he did make some sounds and these might have helped convince Mary Bateman that the farm was haunted.’