Malcolm Bright

It always pleases him do much when he says something that makes Will light up.

"Very specifically on the psychology of murder. Even more specifically on what the difference is between someone who kills once, for some kind of tangible reason and someone who goes on to kill again and again and how the tipping point generally lies in their second murder," Malcolm explains. "Something triggers the first kill. Anyone can kill someone. But the next kill? And the next? What makes them do that?"