She approached them, followed by the dog.

‘Good evening?’ she said, polite but unsmiling. Her voice had a faint accent. Normally good at regional accents, Roy Grace could not immediately place hers. A Midlands accent she was trying to suppress, perhaps.

‘Mrs Rebecca Watkins?’ Grace asked, again displaying his warrant card. He repeated his and Polly’s credentials. ‘We’d like to have a word with you – is there somewhere we can talk privately?’ Then, lowering his tone, he added, ‘Discreetly?’

A shadow flitted across her face. ‘What do you mean by that?’ She looked for a moment at Polly, a tad too closely. ‘Didn’t I see you at my office earlier this week?’

‘Yes,’ Polly said. Then, lowering her voice, ‘We’d like to talk to you about your whereabouts this afternoon, Mrs Watkins.’

She jumped. It was as if she’d just stuck a finger into an electrical socket.

There was a faint hiss and whirr from upstairs – the sound of a shower running, Grace thought. ‘If it’s not convenient here, perhaps you could accompany us to Police HQ?’

‘Here’s fine,’ she said stiffly. She indicated a door on their left, opened it, led them through and closed it behind her.

The detectives entered a lounge, bizarrely decorated in vivid colours. There was a life-size model tiger, a silver giraffe head on one wall and some very strange modern art on the others, as well as a white baby grand piano.

Rebecca Watkins gestured them to one of two curved blue sofas facing a glass coffee table, inside which – and Grace didn’t care to look at them too much – was an assortment of preserved spiders and beetles. She then closed the door firmly, ensuring it clicked shut.

Grace looked at the piano. ‘Do you play?’ he asked, trying to break the ice and to get a reading from her face.

‘My husband,’ she said dismissively, as if it were an affliction rather than a talent. She sat down opposite them, bolt upright, crossing her legs and then her arms.

Defensive pose, Grace noted.

‘Who’s the entomologist?’ Polly asked.

The woman threw a casual glance down at the table. ‘Oh, that’s my husband, too. Not my thing at all. Critters, yech!’ She shuddered.

Grace wondered, curious, if she didn’t like the insects why she allowed it to be a centrepiece of their living room. She didn’t look like a pushover to him.

‘So, officers, I must ask, do you know Bill Warner – he’s a cousin of mine?’

Grace nodded. ‘Yes, one of the best police officers I’ve ever had the privilege to work with.’

‘Lovely man.’

‘He is,’ Grace said. Then, lowering his voice a few octaves, he said, ‘Mrs Watkins, could you tell us your movements over the past four hours? As I said, if you would prefer to talk somewhere more discreetly we could go to Police HQ?’

She locked eyes with him fleetingly. ‘Why would I need to talk somewhere discreet? I’ve nothing to hide.’