‘The pathologist says the normal signs of auto-erotic asphyxiation are missing, he had no previous predilection for this sort of stuff, the post-mortem hypostasis is dodgy so the body might have been moved, Steph can’t be sure on time of death, and—’

‘And who are you saying killed him? The wife? The wife with an alibi?’

‘Maybe. The best friend isn’t telling us everything.’ Robin’s acutely aware of how daft this is starting to sound. ‘I just have—’

‘A feeling, yes.’ Baker taps his fingers on the desk. He looks to Freya. ‘And what do you think, West?’

Robin told her not to come, he didn’t want her to get caught up in this mission of his, but she insisted. He watches as a blush of red creeps up from the neck of her shirt.

‘I agree with DS Butler, guv,’ she says. ‘Something doesn’t feel right.’

Baker rolls his eyes. Robin’s got a lot of respect for his DCI. An ex-boxer, Baker’s once large muscular chest has given way to flab, but otherwise he’s an intimidating figure. A strong black man, he’s worked his way through the ranks, pushing aside every bit of institutionalised racism he encountered and proving himself through hard graft. He’s an experienced cop, but he’s more than that to Robin – he’s a trusted friend. But today he’s his boss. And a grumpy one at that.

He runs his hand over his shiny bald head. ‘Fine,’ he says at last, in his strong London accent. ‘Look a bit closer. But do it on top of your normal caseload; I don’t want your other investigations to suffer as a result of this ridiculous quest.’

Robin and Freya both stand up quickly, about to leave before their boss changes his mind.

‘And you have zero budget, you hear me?’ Baker shouts after them. ‘Zero!’

‘You should have stayed out of it, Freya,’ Robin whispers as they walk quickly down the corridor. ‘You didn’t need to bugger up your reputation on this, too.’

‘It’s fine,’ she replies quietly. ‘It’s important.’ She stops in the corridor, and he pauses in response. Her face is solemn; it’s clear how seriously she’s taking this case. ‘But Sarge,’ she says. ‘How are we going to find anything? Baker’s right, we have nothing. It’s the perfect murder.’

‘The perfect murder?’ he repeats.

‘Yeah. Where no one has any idea who did it or why. Where they leave no clues, no exhibits, no lines of investigation. Where nobody even suspects it is a murder.’

But she doesn’t wait for Robin’s response. She smiles, her expression pinched. ‘I’ll get back on it,’ she says, and hurries off, leaving him standing in the corridor.

Robin stares at her departing back. After the jubilation of Baker’s agreement, Freya’s words have shaken him. Because Robin knows all about perfect murders.