‘A line from an Emily Dickinson poem,’ said Sam. ‘The same poem Rhian Douglas had a line from in her little white book.’

‘Combingham Police had high hopes a witness might turn up,’ Dunning raised his voice a fraction to remind them all of who was supposed to be speaking. ‘Someone who saw Billy being let in through the door next to the toyshop that leads up to the flats. But no one saw anything, or if they did, they didn’t come forward. Despite Linzi’s flat being opposite a chip shop, a café and a betting shop, there were no witnesses to speak of. Probably a case of too much going on in a busy shopping area, so that no one saw anything.

‘Linzi, like Rhian, was shot in the back of the head – in the lounge, though, not the kitchen. She was found in front of the cabinet where she kept all her Harry Potter paraphernalia. Nothing had been taken, Ahmed told police later, but the doors were open and there was a model of Dumbledore on the floor next to Linzi’s body. We’re thinking maybe Billy asked Linzi to show him the Harry Potter stuff, and when she was facing the cabinet, with Dumbledore in her hand, he came up behind her and shot her. All the people who lived in the other flats above the toyshop were out at work, so no one heard a shot – but that’s not surprising. That road, there’s buses roaring by constantly.

‘On the coffee table in the lounge were two mugs, one containing the dregs of a cup of tea, the other of coffee. We know from Ahmed – who alibied out early and satisfactorily – that Linzi drank coffee always, never tea. Angela McCabe, victim number three, was the same, and at her place too there was one tea, one coffee mug found near her body. At the Rhian Douglas crime scene there were two teas; Rhian was a tea-drinker. I think it’s safe to assume Billy’s a tea-drinker too, therefore.’

‘If I were a serial killer with a strong preference for coffee, it’d probably occur to me to ask for tea at my crime scenes,’ said James Wing.

Simon disagreed and said so. ‘You’re about to do something as momentous as commit murder; you’d want your regular go-to comfort drink. It’s not as if “Suspect drinks tea” or “Suspect drinks coffee” is going to bring a police team to your door – millions drink both.’

‘True if your pool of potential suspects is everybody out there,’ said Kerensa Moore. ‘Less true if we narrow it down to a few possibles. In that scenario—’

‘In that scenario, we fall to our knees and praise the Lord,’ said the Snowman. ‘Can we press on? Who’s doing Angela McCabe?’