‘Here’s something else that’s weird: I’m not Billy’s type. I don’t have a best friend, or any friends. All the evidence suggests they’re more trouble than they’re worth. Point is, I’m not part of a pair – yet the line of poetry in the book I was given is one of a pair with the one from the hospital noticeboard. They’re from the same poem, by Edna St. Vincent Millay. Verse one contains both lines: “Death devours all lovely things;/Lesbia with her sparrow/Shares the darkness,—presently/Every bed is narrow.” I wanted to ask you … did the two pairs of best friends Billy killed get lines from the same poem? As me and the cancer ward noticeboard, or as each other?’

‘As each other,’ says Gibbs. ‘First two, the lines came from a poem by a woman called Emily Dickinson. Second pair, the writer was an Ella Wheeler Wilcox. Both poems, like yours, were about death.’

‘And all three by female American poets whose first names begin with E.’

‘Do you think that means something?’ He’s not looking at me, and sounds as if he’s asking himself.

‘I’ve no idea. I mean, if you want American women poets who write about death, why not pick Sylvia Plath? She’s the obvious one.’

‘You’re the anomaly,’ Gibbs neatly summarises how I feel about myself most of the time. ‘The lines come in pairs. All Billy’s victims so far are pairs of best friends, but you don’t have a best friend. Yet you get a book containing a line that’s one of a pair. A man – maybe Billy, maybe not – hands it to you instead of leaving it in your bag or among your possessions, and then you’re not murdered weeks or even months later.’

‘No need to sound so miffed about it.’ I smile at him. ‘There’s still time.’

‘But you don’t consider yourself to be in danger, do you?’ This sounds like an accusation.

‘I believe I might be, yes.’

‘You don’t seem scared.’

‘I’m not.’ Not for myself. ‘Logically, it seems I might be on this guy’s list. Emotionally, I can’t really get far enough past the unpleasantness of witnessing a cancer death at close range to believe in these murders that seem so … well, sensational. Improbable. I know they’re real – I’ve heard about them on the news – but they don’t feel real.’

‘They do to the loved ones left behind.’