‘Well, I read the news, but … I couldn’t in all honesty describe myself as someone with a social conscience,’ Sellers said. ‘If I had my way I’d win the lottery and live out my days as a tax exile with my own private island. My wife says I’m a selfish … er, a selfish git.’

Lane laughed. ‘We’re all selfish much of the time. That’s only human. But of course you have a social conscience! You’re a policeman. Every day you do your best to make the world a safer place for everyone in the Culver Valley. Don’t you?’

‘I s’pose.’

‘Well, then. Anyway, I’m not saying for a moment you should stop watching the news. In fact, I think it’s great that you can and do, and still remain the person you are!’

Sellers didn’t know what she meant. He was about to ask when she said, ‘I want to help you in any way I can, but insofar as it’s possible, I’d rather not hear any details of murders or cruelty – if that’s all right?’

‘Oh.’ Normally people wanted to hear all the repulsive details and weren’t nearly as keen on the helping part. ‘Yes, that’s no problem at all. I mean … if you want, I can tell you nothing about Billy and stick to asking questions. If you don’t mind not knowing any context?’

‘That’s fine.’ Lane smiled.

‘Although because you’re involved – only at several removes, so it’s nothing to worry about … But because your name’s been … mentioned in connection with Billy – this case, I mean – I’m going to need to ask you where you were on several dates, if that’s possible. It’s really nothing to worry about.’

‘Absolutely fine. Shall I get my diary?’

‘That’d be great, thanks. For this year and last year, if you have them.’

‘Yes, I do.’

Lane rose gracefully and left the room, closing the door carefully. Sellers heard footsteps on the stairs, then nothing for about ten seconds, then more footsteps.

The door opened silently and she reappeared with two black leather A4-sized books. One by one, Sellers told her the dates of the five murders. It soon became apparent she wasn’t a suspect. Two of the five days Lane had spent at a private hospital in London doing group therapy with breast cancer patients from 9 a.m. until 4 p.m. Another two had been spent here at her home, seeing private clients. She couldn’t share their details now, she explained, because of confidentiality, but she could certainly contact them and ask if any of them were willing to speak to Sellers and vouch for her. On the most recent Billy-kill day, Tuesday, 6 January, Lane and her husband Duncan had been in Paraty, Brazil, on holiday.