‘You think it was a kind of message?’ Perez wasn’t sure what he made of that. He’d never been one for conspiracy theories and weird signals. But if he’d considered weird theories and ideas last October in Fair Isle, Fran might still be alive. Now, maybe, he should be a bit more open-minded.

‘Probably not!’ Willow grinned at him. ‘You think I’m being daft, don’t you?’

‘I think it wouldn’t do any harm to check if there’s ever been a connection between Markham and the Fiscal. We’d do the same thing for any other witness. She might have come across him when she was a lawyer in Edinburgh. She’s only been here for a few years.’

‘I’ll get one of my team in Inverness to do the digging,’ Willow said. ‘There’s a lad who’s a wizard at that kind of thing. Sit him in front of a screen all day and he’s happy.’ She got to her feet. It took one supple movement, not a scramble. Perez thought if she weren’t so tall, she could be a dancer or a gymnast. ‘We should get back to the station and make some calls. I need to find out if anyone was in the museum yesterday afternoon. They might have seen the car being dropped off there. I mean it was daylight and it was an unusual vehicle. Maybe you could take that on, Sandy? Again it’s more a job for a local.’

Sandy nodded. He seemed half-asleep in his chair. ‘No problem. I’ll get on to it first thing. I’m surprised we haven’t heard more about the car already. Folk will know that we’d be interested.’

‘From what you’ve told me, that’s the odd thing about this case.’ It came to Perez that this was astonishing. Different from any other investigation he’d ever known. ‘Nobody saw anything. Not the car turning up at Vatnagarth or the body being put in the yoal. It’s as if the killer was invisible.’ He looked at them to make sure they understood. ‘You know what it’s like here. You think that Shetland’s a big and empty place, but cut a peat bank five miles from the road and someone will have seen you do it. This murderer is clever. Or very lucky.’

‘There was a thick fog in North Mainland,’ Sandy said. ‘The sort of fog you’d lose your way in. That’s why nothing was seen.’

‘Lucky then,’ Perez said. But he wasn’t sure he believed in that sort of luck after all.

Willow said they’d make their own way back to the station. ‘The exercise will do us good, and it’ll help me get a feel for the place. I don’t really understand a street map until I’ve walked it.’