Sam Komobothekra, in Simon’s place, would agree without question. As Sam himself had admitted, he was better suited to hand-holding than to police work. Charlie would say, “If I see him doing it while I’m talking to him, I’ll mention it—how does that sound?”

Simon found himself unable to respond directly to the question. Helping people to live happier lives wasn’t his job; solving murders was. He wanted to say, “No,” but that would have sounded too harsh.

“Can I come in?” he said instead.

Jennifer nodded and moved aside so that he could pass. She pointed down the hall. Simon looked and saw the two of them reflected in the largest mirror he’d ever seen. It took up a whole wall. “Bryn’s in the kitchen. Straight down to the end, turn right, then left, straight along again—it’s at the far end of the house. Do you want me there or not?”

“I’d rather talk to him alone if that’s all right,” said Simon.

“Fine. If he forgets to offer you a cup of tea, ask for one. He’ll probably forget. Oh, one thing.”

“What?”

“If he asks you what you think about what he did, what’s happened to him, whether he should be banned from sprinting for life, what’s your answer going to be?”

“I’ll say I’m not here to discuss that.” Simon saw that this wasn’t enough for her. “Or I’ll tell him the truth—I know nothing about competitive sport and what the rules should or shouldn’t be. I don’t have a view. I’ve never thought about it.”

“If he tells you he’s changed and that he wouldn’t do it again, what’ll you say to that?”

“I’ll say . . . that’s good—I’m pleased to hear it?”

Jennifer seemed to relax. “Thank you,” she said. “Maybe a positive response in real life’ll count for more than all the haters online. I hope so.”

The huge mirror, it turned out, was part of a collection. Simon passed at least twenty more, on his way to the kitchen. It was the Hall of Mirrors—not in Versailles but in Norwich.

Bryn Gilligan didn’t look up as Simon walked into the room. He was hunched in front of a laptop computer, tapping away at the keyboard. His pale ginger hair was wet, and he was wearing a gray terrycloth bathrobe. “Sorry,” he said, looking up. “I meant to get dressed before you arrived, but . . .” He nodded at the screen in front of him. “Are you on Twitter?”

“No,” said Simon, thinking that Bryn Gilligan was one of those rare people who looked much younger than he was. He would probably always have the face of a teenager.

“Very sensible. I’d stay well away from it if I were you.”