‘You’ve met him, haven’t you?’ said Mrs Lowther, between sniffs. ‘You can see he’s harmless. What could he have done to anybody to make them commit an evil act like that, just to get back at him? It doesn’t make sense.’

Her husband nodded. ‘Besides, Brian doesn’t mix with people who’d do that sort of thing. He’s a despatch manager in a distribution centre.’

On the corner table was a set of photographs in silver frames. Smiling faces, boyish grins, a baby balanced on someone’s knee – the Lowthers’ grandchildren. Fry could see that Jack and Liam were fair-haired, with the pale look of their father. But the baby, Luanne, was much darker. The biggest frame contained an entire family group – Brian and Lindsay with all three children, their youngest child held proudly out front, taking centre stage as if it was her birthday or something.

Fry felt an urge to pick the photos up and look at them more closely, but she was afraid it would distract the Lowthers’ attention. Pictures of the fire victims had already been obtained for the case files and the media. She could look at them back at the office, more safely.

Instead, she looked down at her notebook. ‘Could we talk about the house for a few minutes? I mean, your daughter’s address in Darwin Street. I presume you know it quite well?’

‘Yes, of course,’ said Mrs Lowther. ‘We go there often. We were with them when they moved in. I helped Lindsay choose some of the furniture.’

Hearing that, Fry knew she’d have to pick her words carefully when she asked the next few questions, or she was likely to lose Moira Lowther altogether. The untreated polyurethane foam wasn’t her fault, but guilt knew no logic.

‘First of all, the smoke alarm. They had one installed in the kitchen.’

‘Yes, it was installed as soon as they moved into the house. Brian insisted on it.’

‘Who advised him where to put it?’

‘Advised him? I don’t think anyone did. The kitchen was the obvious place. It’s where accidents are most likely to happen.’

‘I see.’

Of course, in one way the kitchen was the obvious place for a smoke alarm. Every day, the fire service could be guaranteed a tea-time call-out to an overheated chip pan somewhere. But if Brian Mullen had bothered to read the manufacturer’s instructions he would have seen a different recommendation. If he’d taken any notice of it, he might have kept his family alive. But there were too many ‘ifs’ in that equation.

Nevertheless, Fry filed away the impression of Brian Mullen as the sort of man who’d toss the instructions disdainfully aside as he whipped out a screwdriver and relied on his masculine instincts to get the job done.