There seemed little point in pressing him because I was already fairly certain that Quinn wasn’t someone Patrick had been to school or university with, so I hung up and gave myself a moment to think. If I called Quinn, I could ask him outright what his connection to Patrick had been and see where it took me – but there was a decent chance I’d spook him and then he’d bring down the barricades. I paused, my thumb hovering over Dial. It was a risk, whichever way I went, but then it was a risk standing here in the rain, three hundred feet from the front door of a man who might have bugged the homes of nine missing people – so I called Quinn’s landline.

His voicemail kicked in again.

This time, I left a message: ‘DI Quinn, my name’s David Raker. I find missing people. I wanted to talk to you about Patrick Perry. I’d appreciate a callback.’ I kept it at that, left him my mobile number and hung up. I didn’t have to wait long for a response: three minutes later, my phone started chiming, the display flashing PRIVATE, and when I answered and said my name, I got nothing in response except silence. In the background, I heard phones, conversation, the low drone of an office.

Finally, a voice said, ‘This is Kevin Quinn.’

‘DI Quinn, I appreciate –’

‘What do you want?’

He was already on the defensive.

‘I’ve been asked by Ross Perry and the families of the people who lived at Black Gale to look into what happened to them.’ I stopped for a moment. I was banking on him knowing all about Black Gale already, but I doubted he would be prepared for a voicemail message out of the blue about it, two and a half years on, especially as it had never been a case at the Met, let alone a case he’d worked himself. Not that he wouldn’t already have followed this entire exchange to its natural end point: I’d worked out that he was Patrick Perry’s source, and now I wanted help.

I quickly tried to allay any sense of enmity or panic he might have been feeling: ‘Just so we’re absolutely clear, I’ve got no interest in anything other than finding out where Patrick went. I’d like to ask you some questions, I’m hoping you can give me some answers – and, once you have, I’ll hang up this phone and we’ll never speak again.’

More silence on the line.

‘DI Quinn?’

Nothing.

‘DI Qui–’

‘I’ll call you back.’

The line went dead.