‘Makes sense to me,’ Gary answered as we went down the stairs. ‘No offence, Castor, but I’d rather have you face this bastard than any of my lads - or me, for that matter. At least you know what you’re letting yourself in for. If we get anything, I’ll call you. But keep your bloody phone turned on for once, all right?’

We parted company at the door and I walked away through the thinning crowd of onlookers. Nothing to see now: just the dead woman’s arm up at the window, raised as if she was waving to us. Gary’s hard-working boys and girls were packing up their circus and the novelty had all worn off. Tomorrow was another working day.

As I walked back up Brixton Hill, I tried my best to think about the circumstances of Ginny’s death without letting the image of her body, sprawled on the floor like a broken toy, intrude into my mind. I didn’t manage it.

What had Asmodeus come back for? Why had he taken the trouble to find her, and then to talk to her before he murdered her? Had he come there with bloody execution already on his mind, or had his gleefully sadistic nature, which I knew only too well, simply got the better of him?

The night was hot and sticky, with the smell of tarmacadam rolling in from somewhere on a lethargic wind. It drowned out the more enticing smells of cooking from closer at hand: someone was having a very late supper of jerk chicken, and it wasn’t going to be me.

Perhaps because I’d been playing my whistle such a short time ago, my death-sense was fully awake. I saw a ghost sitting in the middle of the road, its knees drawn up to its chest and its head bowed. Hard to tell if it had been a man or a woman; after a while, unless you had an unshakeable self-image when you were alive, the fact of being dead tends to erode you at the edges. Little by little, you start to dissolve - unless someone like me gets to you first and wipes the slate clean all at once.

There was a much more recent ghost standing in the mouth of an alley just before the junction with Porden Road: a young man in a faded blue shell suit, conducting one half of the conversation he’d probably been having just before he died. The sound reached me as a thin mosquito whine. In his chest there was a deeply shadowed hole about the size of a grapefruit.

In a doorway a little further on, an old woman sat clutching a Tesco carrier bag like a baby in her arms. I could tell without looking that she was dead: not a ghost this time, but risen in the body, a zombie. The smell of putrefaction hung around her, as solid as a curtain.