For Jake Davis, it all ended with a knock on the door. It was lunchtime on a summer’s day in 2011. Davis, 18 at the time, had cooked pasta with spinach. He was playing Tetris on a Dell laptop in his bedroom. He’d been anxious and paranoid for months, living on his own in a tiny council house on a tiny estate near Lerwick, in the Shetland Islands. He’d tried to cover his tracks. But he hadn’t thought of everything. He knew he’d made mistakes.

When he opened the door, there were six people outside. Five men and a woman. One of the men said, “Are you Jake Davis?”

“Uh, yes.”

“We are arresting you,” he said. The five men escorted Davis into his living