‘Give me a sec,’ he said to Bloom. He needed to concentrate. People rarely picked a location at random. In MI6 he used to run sessions with new recruits in which he instructed them to select a location to meet a source in a city they weren’t familiar with. They could choose the city and the specific location. The only rule was it had to be somewhere they didn’t know well. His job was to guess where in their given city they’d selected, to within a radius of one mile. They all went away to research their locations and then returned with a smugness that said: You’ll never guess this. But he usually did, because people couldn’t escape their own unconscious biases. If they preferred to travel by public transport, they’d pick somewhere within walking distance of the train station. If they preferred to drive, they’d go for somewhere near a car park – especially if they had a decent motor. If the recruit in question was a football fan, they’d pick a point within a mile of the stadium. The more Marcus knew about them, the easier it was to guess. It’s surprisingly hard to pick something at random. He was banking on that being true for psychopaths, too.

He looked at the options again. St John was one of Jesus’s disciples. Was religious symbolism likely for a psychopath? Sovereign signified royalty and independence, and Wellington, if you were talking the Duke of Wellington, was a master of war. Either of those could work. He thought about the message again. The lovely Sarah will be taking a closer than usual look at the view. What could be seen from the top?

‘If you were standing on the top of each of these car parks, what would you see?’ he asked the receptionists.

The older woman looked down as she thought about the question. ‘From St John’s, you’d see the top end of town, towards the university. Wellington Street goes out towards the ring road, so maybe you’d see all the business buildings along the waterfront. But like I said, I don’t know exactly where that car park is. And from Sovereign Square, you’d see this hotel and the train station.’

‘The train tracks?’ said Bloom in Jameson’s ear.

‘The station or the tracks?’ he asked, but he was already moving. Sovereign Square was the largest, so probably the highest, had a name that signified standing out from the crowd, and overlooked the train line. That was enough. His gut said it was the place.

‘Both,’ called the receptionist as he dashed towards the door.

‘I’m going to Sovereign Square, Augusta. It’s the largest, so probably the tallest. Why are they doing this? If this is your Seraphine girl, why is she after the people I care about?’

Bloom sighed. ‘I expect because you’re the person I most care about.’