Their progress across town was slow, the rush-hour stream of buses, cars, vans and trams clogging the tight mesh of streets that had been built for horses and carts two centuries before. But as they left the city centre and moved into the outer suburbs, the traffic thinned and Carol had to work a bit harder at staying in touch but unobtrusive. From the route Taylor had taken, it looked as if he was heading home. Carol couldn’t help wondering where he was in his murderous cycle. Did he have another victim lined up? Was there already another woman in captivity? It was clear that he kept them before he killed him. Might he be headed back to an imprisoned victim right now?

The short-term answer to her question came just before the ring road, when he pulled off into an out-of-town development packed with the traditional selection of carpet warehouse, fast-food outlet, discount sofa store, white goods and computer emporia and a sprawling DIY megastore. For a brief uncomfortable moment she was right behind the BMW. She hung back while he parked in a distant area of the car park then watched as he jinked through the lines of parked cars to arrive at the DIY store entrance. He paused to retie his shoelace, and as he set off again, she could see he had a slight but noticeable limp. Just like Tony.

‘Yes,’ Carol hissed triumphantly. She left the Landie in the first available slot and ran after him. By the time she made it through the door, he’d vanished from sight. She hurried up to the aisle that bisected the shelves at the midway point and walked briskly along, scanning in both directions as she went.

She spotted him in the locks and home security section, checking padlocks and chains. It was a terrible cliché, but she supposed clichés only reached that status because there was truth in them. She turned down the next aisle, then came up behind him, pretending an interest in brass and chrome door furniture. He didn’t turn his head. He selected a heavy padlock and started walking towards the rear of the store. Carol followed, keeping her distance and constantly ready to turn aside and examine whatever was on the shelves.

He was making for the trade counter, she quickly realised. Even though this was a different chain from the store she used for her own building requirements, they all had a similar layout. Taylor clearly knew his way around, making straight for the doorway that led to the timber-cutting area. He must be ordering or collecting made-to-measure wood, she thought. She found a vantage point where she could keep an eye on the doorway without looking suspicious, and stared unseeing at a catalogue of bathroom fittings.