“We should start interviewing all the people who had contact with Geoffrey Wheatcroft or Jason Dunlop.”

There was an ironic cheer as one of the portable floodlights was restarted.

“That’s an ambitious list of suspects,” said Nightingale.

“Then we start with the ones who knew both of them,” I said. “We can do it under the pretext of investigating Jason Dunlop’s murder.”

“First,” said Nightingale, “I want you to go and secure Smith’s office.”

“You don’t need me here then?” I asked.

“I’d rather you didn’t see what’s in there,” said Nightingale.

For a moment I thought I’d misheard him. “What is in there?” I asked.

“Some very beastly things,” said Nightingale. “Dr. Walid has people coming in who’ve handled this sort of situation before.”

“What sort of situation?” I said. “What sort of people?”

“Forensic pathologists,” he said. “People who’ve worked in Bosnia, Rwanda—that sort of situation.”

“Are we talking mass graves here?”

“Among other things,” he said.

“Shouldn’t I—”

“No,” said Nightingale. “There’s nothing in there that it would profit you to see. Trust me in this, Peter, as master to apprentice, as a man who’s sworn to protect and nurture you. I don’t want you going in there.”

And I thought—do I really want to go in there?

“I can see whether No-Neck Tony knows anything while I’m at it,” I said.

Nightingale looked relieved. “That is an excellent idea.”

Stephanopoulis lent me the Somali ninja girl whose name was Sahra Guleed and who turned out to be from Gospel Oak, which is just up the road from where I grew up—different school, though. When two ethnic officers meet for the first time the first question you ask can be about anything but the second question you ask is always, “Why did you join?”

“Are you kidding?” said Guleed. “You get to legally rough people up.”

The answer is nearly always a lie—I knew an idealist when I saw one. Despite the drizzle, the Saturday-night crowds were thick on Old Compton Street and we had to dodge our fair share of drunks. I spotted my old mate PC Purdy loading a dazed-looking middle-aged man into the back of an IRV. The man was dressed in a pink tutu and I was sure that I knew him from somewhere. Purdy spotted me and gave me a cheery wave as he climbed into the front of the car—that was him out of the rain for the next couple of hours.

Since, with a bit of persuasion earlier, Alexander Smith had given permission for us to search his office, I had his keys. But when we got to the door on Greek Street it was ajar. I looked at Guleed, who flicked out her extendable baton and gestured for me to take the lead.

“Ladies first,” I said.

“Age before beauty,” she said.

“I thought you liked roughing people up.”

“This is your case,” she said.