‘But instead,’ he said, ‘you waited. You waited all that evening, having watched her leave the building. You must have been pretty tightly wound by then. You’d had time to formulate a rough plan. You’d been watching the street; you knew exactly who was in the building, and who wasn’t; you’d worked out that there might just be a means of getting clean away, without anyone being the wiser. And let’s not forget – you’d killed before. That makes a difference.’

Bristow made a sharp movement, little more than a jerk; Strike tensed, but Bristow remained stationary, and Strike was acutely aware of the unattached prosthesis merely resting against his leg.

‘You were watching out of the window and you saw Lula come home alone, but the paparazzi were still out there. You must have despaired at that point, did you?

‘But then, miraculously, as though the universe really did want nothing more than to help John Bristow get what he wanted, they all left. I’m pretty sure that Lula’s regular driver tipped them off. He’s a man who’s keen to forge good contacts with the press.

‘So now the street’s empty. The moment has arrived. You pulled on Deeby’s hoodie. Big mistake. But you must admit, with all the lucky breaks you got that night, something had to go wrong.

‘And then – and I’m going to give you full marks for this, because it puzzled me for a long time – you took a few of those white roses out of their vase, didn’t you? You wiped the ends dry – not quite as thoroughly as you should have done, but pretty well – and you carried them out of Flat Two, leaving the door ajar again, and climbed the stairs to your sister’s flat.

‘You didn’t notice that you’d left a few little drops of water from the roses, by the way. Wilson slipped on them, later.

‘You got up to Lula’s flat, and you knocked. When she looked through the peephole, what did she see? White roses. She’d been standing on her balcony, with the windows wide open, watching and waiting for her long-lost brother to come down the street, but somehow he seems to have got in without her seeing him! In her excitement, she throws open the door – and you’re in.’

Bristow was completely still. Even his knee had stopped jiggling.

‘And you killed her, just the same way you killed Charlie, just the same way you later killed Rochelle: you pushed her, hard and fast – maybe you lifted her – but she was caught by surprise, wasn’t she, just like the others?

‘You were yelling at her for not giving you money, for depriving you, just as you’ve always been deprived, haven’t you, John, of your portion of parental love.