It was true. There were hundreds, perhaps thousands, of knives glinting under the harsh strip lighting. Knives that had been seized, found, dumped, bagged as evidence or surrendered during an amnesty. So many knives that I didn’t see how I could fail to find a suitable candidate for the one that had cut the throats of the banker and the unknown man.

The uniformed officer had fallen into step beside me. He cleared his throat nervously.

‘It’s PC Greene, sir,’ he said. ‘PC Billy Greene? From that morning at the bank? You told me to breathe. When I came over all funny.’

I looked at him properly and remembered the young officer who was good for nothing after finding the body.

‘PC Greene,’ I said. ‘You don’t call me sir just because I’m in plain clothes.’ I was wearing my black Paul Smith wedding suit. Savile Row being still a bit beyond my pay grade. ‘I’m a detective constable – DC Wolfe. Exactly the same rank as you. You can call me Wolfe. You can call me Max. You can call me pretty much whatever you like. But if you call me sir then you make both of us look stupid. You do know that a DC has exactly the same powers and authority as a uniformed PC, don’t you?’

He looked embarrassed. ‘Of course, sir— Max, er, DC Wolfe. But anyway, I didn’t thank you. A lot of them were laughing at me for wimping out that day. You helped. It definitely helps. The breathing.’

‘You’re not on the street any more?’

His white face flushed red. ‘They’ve put me on desk duties. Reassigned. A canteen cowboy.’ He laughed miserably. ‘They think I fell to bits.’

I grimaced. ‘That’s a bit hard.’

Greene gestured at the knives, changing the subject. ‘See what you’re looking for?’

‘Not yet.’

I walked between the tables, looking at the knives in their careful lines. Throwing knives. Hunting knives. Bowie knives. Knives so small and thin they could fit into a credit card holder. Samurai swords. Carpet cutters. Gurkha kukris. Rust-dappled Stanley knives. And the height of knife fashion – compact semi-automatic folding knives, with titanium handles and stainless steel blades, knives that whipped out like a gunslinger drawing his Colt 45.

I picked one up and looked at it in my hand.

‘We’re getting a lot of those,’ Greene said. ‘Gang members like them. You think it might be something like that?’

‘I don’t see how it can be,’ I said, replacing the knife. ‘It’s not long enough. I figure what I’m looking for is about twelve inches long. Most of it blade. It has to be a blade that’s long and thin and I guess double-edged. Something that’s made to cut throats.’

He swallowed hard. ‘This is about Bob the Butcher, isn’t it?’

‘Who is Bob the Butcher?’