O’Connor shrugged. ‘That was long before my time, but Robert did tell me once why they had it done. It was for two reasons apparently. The first was because Mary was uncomfortable knowing that the previous owners died down there. Robert kept promising to replace the door with a wall but he didn’t get around to it until some years after they moved in. The second reason was that both the outside and inside doors to the cellar were left open one day and a fox wandered in and gave them all a fright.’

‘And are you aware that there’s a small enclosed space behind the wall that was installed below the stairs?’

‘That’s news to me,’ O’Connor said. ‘I know there’s a door at the top of the cellar steps but it was always locked. I assumed there was nothing beyond it but the wall.’

‘Then you know nothing about a peephole in that wall? We believe it was used to spy on the family.’

He seemed genuinely shocked. ‘Why the fuck would anyone do that?’

‘That’s what we’d like to know.’

‘Well it wasn’t me and I can’t begin to imagine who it would be.’

‘Did many people have access to the cellar?’ James asked.

‘Only the family. It was kept locked most of the time and I rarely went in there, which suited me because I found it a bit creepy.’

‘Would I be able to take a look at your shoes, Mr O’Connor?’ James asked suddenly.

O’Connor cocked his head on one side and frowned. ‘What’s that got to do with anything?’

James explained that shoeprints were found at the scene of the crime.

‘We’re going to be examining the shoes of everyone we talk to,’ James said. ‘By taking pictures of the soles we can help eliminate the owners from our enquiries.’

O’Connor pointed to the shoes he was wearing. ‘All I’ve got are these, plus a smarter pair out in the hallway cupboard and some wellies. You’re welcome to take photos, and if you suspect I might be hiding some then feel free to look around.’

James took him up on both offers. He photographed the soles of the shoes O’Connor had on as well as those in the hallway, and noted they were all size tens. Then he went from room to room until he was satisfied that there weren’t any more hidden away.

Finally, he asked O’Connor if he would mind providing a DNA sample, which he had no problem with.

‘Thanks for being so helpful, Mr O’Connor,’ he said after he took down the man’s mobile number. ‘I really appreciate it.’

As James stepped outside, he pointed to an ageing Vauxhall Corsa that was parked at the kerb in front of the house.

‘Is that your car?’ he asked.