‘That’s why he got hammered. And when Izzy found him, he told her what he’d done, didn’t he? When he was drunk, he told her he’d killed someone?’

‘Izzy confronted Jen about it this afternoon. Jen begged her to keep it secret but Izzy wasn’t having any of it because of what happened to her fiancé.’

I remembered a packed church, standing room only, Izzy lightning-struck with grief for Mark, the man she had been about to marry. ‘Killed in a hit-and-run, and they never found the driver. There was absolutely no way she was going to be party to that happening again, was there?’

‘Not in a million years.’

‘The one crime she was absolutely never, ever going to overlook, no matter who was involved. Because it happened to her.’ I took a deep breath. ‘She was about to tell me this afternoon but I was too pig-headed to listen. And that’s when the fire started.’

‘Yes.’

A cloud covered the sun, the temperature dropping a few degrees as the wind grew stronger.

‘Fires started in more than one place, a distance apart, to ensure the flames take hold and can’t quickly be put out is classic fire-setting behaviour – I’ve seen it in arson cases before. It suggests deliberate intent, rather than teenagers messing about.’ I shook my head. ‘I knew there was something off about it as soon as I saw it.’

‘I had no idea Jen would go as far as she did,’ Sean said. ‘No idea what she was capable of.’

‘She was determined to keep it from me, at all costs.’

‘She was.’

The picture was becoming clearer, but there was still one crucial point that I didn’t understand.

‘Jen and Alistair are our friends and we want the best for their boys, I understand that. But what I don’t understand is, why didn’t you tell me about this?’

He stared at me as if the answer was obvious.

‘Because of who you are, because of what you do. Because of what you’re like. The truth, the whole truth and nothing but the truth. It was even one of your bloody colleagues that went out to gather evidence at the scene of the accident. If I’d told you, it would have put you in an impossible situation, and we both know what you’re like: everything is black and white in your world, you would have marched me down to the station in five seconds flat to change my statement.’

I considered this for a moment.

‘You’re probably right.’

‘You know I am.’

‘They can’t stand outside the law. No one can.’

‘Maybe not. But there’s another reason I didn’t tell you. A much more important reason.’

‘What reason could there possibly be for withholding evidence and impeding a police investigation into a serious accident?’