Page 22 of The Final Vow (Washington Poe #7)

‘Tell me again, Tilly,’ Poe said. ‘And for fu . . . flip’s sake, use smaller words this time. And don’t say central limit theorem again. No one but you understands what that is.’

‘In the sixteenth century,’ Bradshaw said, ‘Gerolamo Cardano, the Italian polymath, introduced binomial coefficients to the Western world. He—’

‘Tilly,’ Flynn warned. ‘Will you please, for the love of God, say it normally?’

‘Cheese and crackers, you guys are dumb,’ Bradshaw mumbled. She thought for a second. ‘Do you know what dice are? You might have used them if you’ve played snakes and ladders? Or Monopoly?’

Silence.

‘Jeez-Louise,’ Bradshaw said. ‘They’re cubes with dots that signify numbers.’

‘A bit less sarcasm, please,’ Flynn said. ‘We know what dice are.’

‘I wasn’t being sarcastic.’

‘Start from the beginning, Tilly,’ Poe said. ‘Tell us what dice have to do with these murders.’

They had moved out of the circus marquee and into a command trailer.

Archie had wanted to know what Bradshaw had discovered but didn’t seem too upset when he was told it would need to remain confidential for the time being.

Poe was in no doubt he’d find out soon enough.

He seemed to be getting his intelligence in real time.

His final words to Poe had been, ‘Remember, there’s a bottle of the Macallan M at the end of this monochrome rainbow, Sergeant Poe.

’ Mathers had asked everyone to leave, and despite the murder of Jools Arreghini being a Thames Valley investigation, the cops in the trailer had quickly acquiesced.

Bradshaw started again. She chose her words carefully this time.

‘If we discount that someone is hiding the murder of one victim in among a bunch of other victims, like Jools Arreghini being killed because her father’s a rotten egg, then we are left with only one explanation: he’s choosing his victims at random.

If he weren’t, I’d have found the connection by now. ’

‘But you’ve told me many times that humans can’t generate things at random.’

‘That’s right, Poe. We can’t. Our cognitive processes are simply not capable of it. It would be like trying not to think of something.’

‘So?’

‘So, the murder of Jools Arreghini has provided a large enough sample size for me to spot something in the data. Something unusual. I would have spotted it sooner but the murder in Gretna Green was an outlier.’

‘Which is?’

‘If you were a killer who understood that the human brain is incapable of generating things at random, and you knew that trying to would likely lead to your downfall, how would you overcome this?’

Poe thought it through. Eventually he said, ‘I’d find one of those random-number generators on the internet. Or failing that, I’d roll some . . .’

‘Exactly,’ Bradshaw said. ‘You’d roll some dice.’