Without Carol, he had been lost. With Carol, he stood a chance. And the best thing he could do to help her set him free was to focus not on her and how she’d changed and what was going on inside her head, but on the man who was killing a subset of women that she fitted into.

He got to his feet and started pacing. Profiling, that’s what he was supposed to be good at. He needed to think about this killer in those terms. He’d written the introduction to his profiles so many times he knew it by heart. As he paced, he recited it aloud like a mantra to put his head in the right place. ‘The following offender profile is for guidance only and shouldn’t be regarded as an identikit portrait. The offender is unlikely to match the profile in every detail, though I would expect there to be a high degree of congruence between the characteristics outlined below and the reality. All of the statements in the profile express probabilities and possibilities, not hard facts.

‘A serial killer produces signals and indicators in the commission of his crimes. Everything he does is intended, consciously or not, as part of a pattern. Discovering the underlying pattern reveals the killer’s logic. It may not appear logical to us, but to him it is crucial. Because his logic is so idiosyncratic, straightforward traps will not capture him. As he is unique, so must be the means of catching him, interviewing him and reconstructing his acts.’

He stopped and rested both palms flat on the chilly wall. He wished he had a set of the crime-scene photos in front of him; his memory, like his eyesight, was not quite as sharp as it used to be, and a lot had happened since he’d flicked through the photos Paula had shown him. Some things were still vivid, however. The smashed face of the victim. The primitive markings of the bruises that covered her torso. The shaving of her genital area and the sealing of her labia.