‘Because the victim’s windpipe was cut,’ he said. ‘The trachea. There was no air. And you need air to scream. Nobody heard anything because there was nothing to hear.’

We contemplated the body in silence while all over the large office the SOCOs moved in slow motion like scientists examining the aftermath of a biological catastrophe. They were identical in their masks and gloves and white suits, patiently hunting for prints, placing tiny fibres in evidence bags and taking samples of blood from the desk, the carpet and the glass walls. There was a lot of blood to choose from. One SOCO was drawing a sketch. The photographer who had wondered why anyone would want to kill a banker had stopped taking stills and was now filming the room. Small numbered yellow plastic markers were blooming all over the lush carpet as SOCOs harvested footprints for forensics to match against SICAR, the Shoeprint Image Capture and Retrieval database.

Mallory watched them. ‘Most professional hits are very amateur, Wolfe. Is that an irony or a paradox? They’re carried out by thugs hired in the pub. Morons who will kill anyone for some cash in hand. Most professional hits come with a guarantee – they guarantee to do it badly. But not this one. You see how clean that cut is? Most people, cutting someone’s throat, they slash and chop and saw. They make a mess, don’t they? You saw that with your three. About as big a mess as an enraged human being can make to flesh and blood with something sharp. But this looks like just one cut. It almost took his head off, but it’s just one cut. Now who cuts a throat like that?’

‘Someone who knew what they were doing.’ I thought about it. ‘A butcher. A surgeon. A soldier.’

‘You think we’ve got Rambo running around out there?’

‘I don’t know if he’s running around, sir. Maybe he’s sleeping on the streets.’

Mallory nodded beyond the glass walls to the city thirty floors below, spangled with autumn sunshine around the old grey serpent of a river.

‘How many ex-servicemen are sleeping on those streets?’ he asked.

‘Too many,’ I said. I tried to imagine it. ‘He comes in here during the night. To find somewhere warm to sleep. To find something worth stealing. Gets disturbed.’ I couldn’t make it work. ‘But he has to get past security.’

‘Butcher, surgeon, soldier,’ Mallory said. ‘Or perhaps it was someone who had no idea what they were doing. One of Mr Buck’s fellow bankers. One of the cleaning staff. Perhaps it was just beginner’s luck. Or perhaps it was his wife. Apparently she didn’t like him much. Officers were called out to a domestic dispute between Mr and Mrs Buck three nights ago. There was some violence. Did you see the marital bed?’