“I went through the records that you sent over and Professor Geoffrey Wheatcroft didn’t ever formally teach Jason Dunlop but Dunlop did dedicate his first novel ‘For master Geoffrey from whom I gained my true education.’ Isn’t that what you trainee wizards call your teachers?”

Not this apprentice. But master doesn’t mean the same thing to white boys at Oxford. Given the books in Dunlop’s flat it had to mean, barring a really bizarre set of coincidences, that Geoffrey Wheatcroft had taught Dunlop formal Newtonian magic.

I said as much to Leslie.

“Thought so,” she said. “Question is, was he the only one? And if he wasn’t how do we find out.”

“We need to check the Murder Team’s files and see if known associates or nominals track back to Magdalen College around the time he was there.”

“I love it when you talk dirty,” she said. “It makes you sound like a real copper.”

“Do you think you can do that?” I asked.

“Why not?” she said. “It’s not as if I have anything better to do. When are you coming up to see me?”

“Soon as I get a chance,” I said—lying.

“I’ve got to go,” she said. “I’m not supposed to talk too much.”

“You take care,” I said.

“You too,” she said and hung up.

How many apprentices could one master teach? You needed a trained wizard to act as what Nightingale called an exemplar, to demonstrate the form. But I didn’t see why you couldn’t do that with more than one person at a time. It would depend on how motivated your students were. At somewhere like Nightingale’s old school you’d be dealing with your usual range of talent and enthusiasm. But university students learning magic for fun? Nightingale said it took ten years to be a proper wizard, but I’d managed to do quite a lot of damage within three months of starting training—I didn’t think Jason Dunlop, or any fellow students, would be any different.

I fired up the HOLMES terminal and started looking for connections to Oxford University that had lasted beyond his time there. That got me a list of twenty-plus names, mostly former students, whose paths had crossed professionally or, as far as the Murder Team could tell, socially with Jason Dunlop.