‘So, in addition to solving the Bateman case we now know what happened to Simon and Amanda Roth and their baby, Megan,’ DCI Tanner said.

‘That’s right, sir,’ James replied. ‘And it’s all thanks to a bloke who was spying on his girlfriend through a wall.’

‘And do you believe everything Nash said?’

James nodded. ‘Most of it, yes. Evidence confirms he was there on Christmas Eve and witnessed what took place. And I don’t believe he would have stabbed the girl – he loved her. In addition, he’s connected a lot of the dots and we can now answer most of the questions that have troubled us. However, I intend to question him again tomorrow. There’s one thing niggling me and that’s what transpired after the girl was stabbed. He claims he heard the shots but didn’t see what happened. I’m not convinced that’s entirely true.’

‘Any particular reason?’ Tanner asked.

James shrugged. ‘Just intuition. It’s a bit too neat an ending. Have a listen for yourself.’

Abbott had transferred the interview file from her phone to her computer and played it through a speaker so the whole team could hear.

It generated a healthy discussion and raised lots of questions. The general consensus was that William Nash hadn’t made it up, but that James was right to be suspicious about exactly how Mr and Mrs Bateman had died.

The team also agreed that Nash should be charged at the very least with obstruction of justice or withholding evidence. And a decision was taken to release the four suspects still being held in custody.

‘I’ll discuss with the Chief Constable how much information should be shared with the media, given that this story now goes way beyond the Christmas Eve killings,’ Tanner said. ‘It needs to be handled carefully and with some restraint on our part.’

James got Tanner’s permission to break the news about the Roth killings to Giles Keegan. And he made a point of doing so straight after the briefing.

It came as yet another blow to the retired detective.

‘It makes me sick to my stomach to know that I let them get away with it, James,’ he said. ‘I was really convinced back then that they had nothing to do with it.’

‘No copper gets it right every time, Giles. You shouldn’t let it get to you.’

‘Oh, but it will,’ Keegan said. ‘And for the rest of my flipping life.’

James couldn’t wait to get home. It was 7.30 p.m. when he left the station and he felt dog-tired.

At the same time a pulse hammered in his head as he tried to get to grips with the dramatic turn the investigation had taken.