He tore through the rest of the desk until he found a letter with the estate agent’s heading: Anderson and Son. He read the letter in stunned horror. It confirmed the sale of the ground floor flat, 143 Mount Pleasant Street to Jamie Knight and Kirsty Phillips from Ms Lucy Pica. He dug deeper. There was another letter, dated May, confirming the sale of the flat from Letitia Matthews and David Robson to Lucy Pica.

Lucy had bought the flat in her maiden name from Letitia and David and then sold it on to Jamie and Kirsty, making a healthy profit – and getting two new people to torment into the bargain. And as the sellers of the flat, they would have the keys and plenty of time to install surveillance equipment so they could watch and listen to their victims’ suffering to make their pleasure even greater. The recordings of them having sex weren’t made through the ceiling as they’d suspected: as well as the camera in the living room there was probably a microphone somewhere in their bedroom, hidden beneath something, which would account for the muffled sound on the recordings. The keys also gave them the chance to walk into the flat at any time that Jamie and Kirsty weren’t at home.

Jamie threw all the papers to the floor. A wave of anger crashed over him, blinding him. He stood in the centre of the room. The walls spinning around and around, getting faster, everything going white, blurred; going red, crimson, the colour of blood.

He roared. The cry ripped something in his throat, made the room shake around him. He pulled the CCTV monitor out of its cabinet and threw it against the wall. All his working out had made him strong. The monitor hit the wall with a deafening crunch; shards of glass flew across the room. Jamie roared again.

There was only one way to deal with this.

He stomped across the room into the kitchen, throwing open the cupboards beneath the sink. He pulled out bottles of cleaner, bleach, rubber gloves, throwing them behind him. Then he saw what he had hoped to find: a large bottle of white spirit, almost full and extremely flammable. He unscrewed the top and went back into the living room. He splashed the white spirit around, up the walls, over the furniture. He carried it into the bedrooms and splashed some on the beds. He threw some against the poster of Chris. He trailed the stinking liquid from the bedrooms back into the living room.