“Why here?” Siobhan asked. Hogan looked up as if seeing her for the first time. “Hiya, Shiv,” he said with just a trace of a smile. “You here out of curiosity?”

“She’s helping me,” Rebus said, raising his hands.

“Christ, John, what happened?”

“Long story, Bobby. Siobhan asked a good question.”

“You mean, why this particular school?”

“More than that,” Siobhan said. “You said yourself, most of the kids were outdoors. Why didn’t he start with them?”

Hogan answered with a shrug. “I’m hoping we’ll find out.”

“So how can we help, Bobby?” Rebus asked. He hadn’t moved far into the room, content to stay just inside the threshold while Siobhan browsed the posters on the walls. Eminem seemed to be giving the world the benefit of his middle finger, while a group next to him, boiler-suited and rubber-masked, looked like extras from a mid-budget horror film.

“He was ex-army, John,” Hogan was saying. “More than that, he was ex-SAS. I remember you telling me once that you’d tried for the Special Air Service.”

“That was thirty-odd years ago, Bobby.”

Hogan wasn’t listening. “Seems like he was a bit of a loner.”

“A loner with some sort of grudge?” Siobhan asked.

“Who knows.”

“But you want me to ask around?” Rebus guessed.

Hogan looked at him. “Any buddies he had are likely to be like him-armed forces castoffs. They might open up to someone who’s been the same road as them.”

“It was thirty-odd years ago,” Rebus repeated. “And thanks for grouping me with the ‘castoffs.’”

“Ach, you know what I mean… Just for a day or two, John, that’s all I’m asking.”

Rebus stepped back into the corridor and looked around him. It seemed so quiet, so peaceful. And yet the work of a few moments had changed everything. The town, the school would never be the same. The lives of everyone involved would stay convulsed. The school secretary might never emerge from behind that borrowed handkerchief. The families would bury their sons, unable to think beyond the terror of their final moments…