‘Well, there are easier ways to kill somebody, don’t you think? Easier than breaking into their house and setting fire to their sitting room. More guaranteed to get the right results, too – because, if the smoke alarm had been working properly, the Mullens might have escaped.’

‘Perhaps not that much easier, if you want to make it look like an accident.’

‘An accident?’ Fry tapped the Rose Shepherd file. ‘That doesn’t sound like the Foxlow suspect, does it? There was certainly no attempt to make Miss Shepherd’s death look like an accident. Quite the opposite – it was done openly and audaciously, like some kind of warning: “Look, we can get to anyone, anywhere.”’

‘Ye-es,’ said Cooper.

Fry looked at him sharply. ‘I take it you’ve formed a different opinion, Ben?’

‘Well, just because there was that difference it doesn’t necessarily follow that they weren’t connected, does it? Our suspects might have had some reason for wanting to make the fire look accidental, but not the shooting of Rose Shepherd.’

‘What reason?’

Cooper shook his head. ‘I don’t know . . .’

‘No. But what we do know at the moment is that Rose Shepherd had connections with a Bulgarian criminal, who’s also been found dead. We don’t have any more information on Nikolov until we get PM results and the intelligence files from Sofia.’

‘You almost make that sound like a good thing, Diane.’

‘Well, it means I can focus on the Darwin Street fire for a while. Unrelated, or not.’

A few minutes later, Fry finished reading the postmortem reports on the Mullen family for the second time. She put the report aside, then recalled what Mrs van Doon had said about the victims being confused and disorientated by the inhalation of smoke.

She picked up the phone and rang Scientific Support. Wayne Abbott, one of her favourite people.

‘Wayne, you know you said the fingerprints in the house at Darwin Street all belonged to members of the family?’

‘Yes?’

‘Which members of the family did you mean specifically?’

‘Hold on . . .’ She heard the rustling of paper as he found the right file. ‘Here we go. Well, as you might expect, there were prints from the householders everywhere – that’s Mr Brian Mullen and Mrs Lindsay Mullen. And the children, of course. They were easy to differentiate because of their size.’

‘OK.’

‘Right. Those prints were mostly from the relatively undamaged parts of the house, you understand.’

‘Like the kitchen?’

‘Exactly. I mention that because we lifted a couple of prints belonging to the grandmother, Mrs Moira Lowther. We asked all the family to give their prints for elimination purposes, of course. But hers were only in the kitchen. Nice, smooth surfaces for us to dust, you see. We found none from her husband, though. That doesn’t necessarily mean anything. There was so much damage in the sitting room –’

‘Anyone else on the list?’