A pause. Then Chalmers was back with a smile in her voice. ‘Even better: means I get to break the good news. Be no problem getting a sample after that. We— Oh, hold on. . .’ There was a scrunching noise, as if she’d put a hand over the mouthpiece. Then she was back. ‘Constable Guthrie says there’s a Dr Goulding here to see you? ’

‘Put Goulding in an interview room with Robbie Whyte. I want a full psych evaluation.’

‘Emergency detention? ’

‘And tell Goulding to find out if Whyte’s capable of murder.’ Logan stuck on the brakes, pulling into the slip lane to turn right across the dual carriageway.

‘You think he might be the one who. . .’ There was a pause. ‘Who did he kill? ’

Good question.

Logan gunned the engine, nipping across the carriageway in the gap between a bread van and a minibus. ‘And soon as you’ve got some of Agnes’s DNA, make sure they test it against the necklacing victim and the body we found last night. And the bones from my roof too.’

Chalmers whistled. ‘You think she killed all three of them? ’

‘Bloody hope so, otherwise we’ve got a whole bunch of nutters out there murdering people.’ Nutters. . . Better safe than sorry. ‘Get them to test Robbie Whyte’s DNA against them as well.’

There was a pause, then the intercom buzzed and the gate swung open. Logan edged the car off the road and onto the long gravel driveway. Little chunks of granite pinged and clunked in the rusting wheel-arches.

Wee Hamish Mowat’s house was a big Victorian mansion in solid grey granite. All bay windows and little twiddly bits at the gables and guttering. Logan parked the Fiat next to a bright-red Land Rover Defender that didn’t look as if it’d ever been off road in its life.

His phone rang as he climbed out of the car. He hit the button. ‘What? ’

‘Laz? It’s Tim. . . Tim Mair? Need to talk to you about some hooky merchandise that’s—’

‘It’ll have to wait, Dildo, I’ve got something on.’

‘OK. This afternoon? About three? I’ve got some knock-off custard creams you can cadge.’

Bloody Trading Standards and their counterfeit biscuits. ‘Fine. Three.’

‘I’ll need at least. . .’ Dildo was still talking, but Logan wasn’t listening any more.

The front door opened and there was Tam ‘The Man’ Slessor’s niece, wearing a blue nurse’s uniform, white trainers, and a scowl that could sour milk. She folded her arms across her wide chest. ‘He’s busy.’

Back to the phone.

‘. . .in Mastrick, so it shouldn’t be—’

‘Bye, Dildo.’ He hung up, locked the Fiat and scrunched his way across the gravel to the foot of the stairs. ‘Do you know it’s an offence to provide a false alibi, Ms Slessor? ’