And yet, it was the only thing to do, if I was to find out for sure.

‘Fuck it,’ I said.

On the walk over to the Carney house, I thought through the specifics again. I’d need to search for Deirdre’s DNA. Probably all I’d have for that was a hair sample from the brush I had seen in her bedroom. And I was also looking for male DNA that I hoped would belong to Jeremy Gill. I knew that there was a good chance he hadn’t touched the coaster, but if he had touched Deirdre, she might have transferred his DNA.

After talking to Rhona, I knew that I should be testing for alcohol and possibly a sedative too. DNA was remarkably persistent, as all the cold cases solved in recent years showed. I didn’t know how long alcohol and sedative traces might last but I knew enough to surmise that they could have deteriorated, and possibly disappeared, unless they had been refrigerated and kept at an optimum temperature. But if I could get proof of Gill’s and Deirdre’s DNA together, it would damage Gill, I was sure of it. The very request for Gill’s DNA might be the catalyst I’d need to force him to the settlement table.

I decided to bank on the DNA and forget about the drug and alcohol residue tests for the moment. It was worth a try. And it would cost a lot less than four grand.

While I was waiting for the Carneys to answer the door, I checked my phone. I had had it on silent and in the twenty minutes it had taken me to walk to Turners Cross, I had got seven missed calls from Sadie. Normally, if she wanted me to contact her, she sent one text, and never, ever, repeat-called. I walked backwards towards the garden gate, simultaneously phoning her. As Ann answered the door I mouthed ‘Just a sec’ and turned away.

‘What’s up?’ I said.

‘Something’s happened,’ Sadie said. ‘Something bad.’

She paused.

‘You can’t say it yet, the name hasn’t been cleared for public release. Word came down to us from Dublin this morning. I’m sorry to be the one to tell you but it’s Rhona Macbride. She’s dead. And, Finn, it looks like murder.’

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