‘No such crime in Scots law,’ the investigator interrupted. ‘We refer to it as fire-raising.’

‘I’ll remember that when I write it up.’

The front door stood gaping. Inside, the floor was sodden after a dousing from the fire engine’s hose. The ceiling had been blackened, as had the walls. Clarke doubted Smith would ever get the smell out of her sofa; it would have to be replaced. Same went for the large flat-screen TV, which was dripping water.

‘I use an upstairs room as my office,’ Smith said, ‘so my computer should be fine. Notebook and iPad are in my bedroom.’

Clarke nodded. ‘I’ll stay here,’ she said, as Smith headed for the stairs.

She did another circuit of the living room, then headed through to the kitchen. Dishes still sat on the worktop, waiting until there were enough of them to merit the dishwasher being run. Clarke did the same thing at home. She tried to think what she might have to buy to meet the needs of a house guest. The spare bedroom – never previously used – had become a dumping ground. The ironing board and mound of laundry would need moving and the floor area around the bed clearing of boxes and bits of junk. For want of anything better to do, she stepped outside again. The fire investigator was taking photos of the shattered living room window.

‘Been a spate of these recently,’ he informed her. ‘But mostly happening to people not unknown to Police Scotland.’

‘I’m not sure there’s a connection,’ Clarke told him.

‘Lab will examine the material used, that could give us a clue. In at least two that I’ve worked this past month, the cotton was from the same batch of cloth. Spirits bottles, too, same as tonight. Petrol could have come from anywhere, obviously.’

‘Prints from the glass?’

‘We’ve not been having much luck there.’

‘So whoever did the others wore gloves?’

He nodded and took another photo. The SOCOs were readying to pack up. An emergency glazier had parked his van and was measuring up for temporary boards in front of the broken window. Clarke headed across the street, to where Ogilvie was chatting with a couple in their thirties.

‘Alistair here,’ he said, indicating the man, ‘heard a car leaving at speed. This was just after one a.m., so the timing is right.’

‘Weird that the breaking glass didn’t wake me. Though maybe it did, and that’s how come I heard the engine.’

‘A throaty growl,’ Ogilvie repeated for Clarke’s benefit.

‘Terrible thing to happen,’ the man’s partner added. ‘Laura’s such a lovely person. Will they come back, do you think? I mean, are we safe in our beds?’

‘Perfectly safe,’ Clarke assured her, leading Ogilvie a few paces away. ‘So what happens next?’ she asked him.