‘And you saw them over the years?’

‘Oh yes. I used to call to them regularly, it was the highlight of my week. Always in their house, of course. They never came back to Rowanbrook.’

‘Well, until Liz moved there. Jesus. You must have got a shock when that happened?’

Ruth laughs softly. ‘That’s as close as I ever came to having a heart attack.’

I stop for a moment, remembering a conversation with Liz. ‘I’d forgotten this, but she told me that when she was starting out as an estate agent, her now-husband was viewing a house in Rowanbrook, and she swapped with a colleague so she could show it to him, because she fancied him. Jeez. What are the chances.’

Ruth looks surprised.

‘I think you picked it up wrong. She did switch with a colleague. But it was to see the house, not the man. Santa Cruz.’

‘Oh. But why?’

Ruth sighs. ‘Mary got rid of almost everything when she sold Number Six. Letters, photographs, videos – things she couldn’t risk bringing with her in case Lizzie found them. She wouldn’t leave them with me, she didn’t want there to be any concrete links between us.’

I nod but don’t interrupt.

‘She was very careful. So meticulous in everything she did, all the hiding and covering up, but when she died and Lizzie went through her old stuff, there was one rogue letter. A letter from one of her cousins back home, addressed to Mary-Ann Holborn in Santa Cruz, Rowanbrook Grove – the house Mary and Robbie lived in before Number Six. Mary named it after her hometown.’

‘Ah, of course,’ I say, thinking of the framed photograph I found in the attic.

‘Yes. Lizzie asked me about it when she found the letter and I was completely caught off guard. What could I say? I remember feeling so flustered, blurting out something about her mother renting there when she was younger. She was baffled, couldn’t understand how neither her mother nor I had ever mentioned that we lived in the same place at one point, but then she forgot all about it. Or so I thought.’

‘She forgot about it until she saw it was for sale?’

‘Exactly. When she realized it was on view that morning, she swapped with her colleague out of sheer curiosity – she wanted to see inside the house her mother had once lived in. A fairly benign event really – it’s not like anyone in Rowanbrook was going to see this adult estate agent and think, “There’s little Lily Murphy” – but then she fell hook, line and sinker for the man who was viewing the house and what should have been a twenty-minute nose around her mother’s old home became something entirely different.’

I nod, remembering now what Liz had said. You never know when a tiny and slightly sneaky manipulation of a work schedule can change your life.

‘Wow. You must have been anxious when she moved in?’