‘Once she’d left, Miff sat down at the table and ate the lasagne herself, loudly announcing it to be delicious. All three witnesses separately reported the same altercation, which I’m sure no one wants to hear in detail again: Linzi claimed it wasn’t the same, it was worse, but couldn’t say how. Miff said if she was accusing it of being worse she must surely be able to explain in what way today’s lasagne was different and worse than usual …’ Dunning raced through the substance of the five-month-old argument in a bored voice. ‘Miff then, er, tried to blame Linzi for having the same thing twice – on the grounds, presumably, that if she never repeat-ordered the same dish, she’d be more likely to avoid dashed hopes and dissatisfaction.’

There was a ripple of laughter around the room – as there had been, traditionally, whenever this particular detail had come up.

‘Linzi said, “But it’s not the same,”’ Dunning went on. ‘Miff said, “Darling, if you don’t want it, I’ll happily take it off your hands.” That’s when Linzi walked out and Miff sat down and gave a public performance of really enjoying the lasagne, for the sake of PR. Though you’d have thought not fighting with the customers might have been a more sensible approach.’

‘Ahmed said Linzi never mentioned this altercation to him,’ Simon cut in again with another detail at risk of being omitted, one that had bothered him a bit. ‘She’d been attacked unreasonably by the owner of the café across the road – why wouldn’t she tell her fiancé?’

‘Because it’s a boring-as-shite story?’ Grace Woolston suggested.

Probably. Simon made the concession silently.

‘After Linzi’s death, fingerprints were found in her flat, as they were at all the murder scenes,’ said Dunning. ‘But different unidentifiable fingerprints in each case, suggesting Billy either wore gloves or wiped away all traces of his or her presence at the crime scenes. I don’t think the latter option’s practical, personally …’

‘Me neither,’ said James Wing. ‘We’d have found a few of Billy’s prints at all four scenes, enough to tell us it was the same person. We know that anyway from the little books, but that’s circumstantial.’

‘Which means we don’t know it,’ said Simon. ‘We mustn’t ever forget that we’re assuming the same person killed all four, because of the books and the other similarities. Doesn’t make it true.’

‘Of course it’s the same killer,’ said Proust impatiently. ‘Can we please not waste time?’

‘The gloves thing bothers me,’ said Grace Woolston. ‘You’re in someone’s house chatting away, and you haven’t taken off your gloves? Wouldn’t they be suspicious?’