He resumed his systematic perusal of the file. Evan Duffield’s statement conformed in most respects to Wardle’s second-hand tale. He admitted to having attempted to prevent his girlfriend leaving Uzi by seizing her by the upper arms. She had broken free and left; he had followed her shortly afterwards. There was a one-sentence mention of the wolf mask, couched in the unemotional language of the policeman who had interviewed him: ‘I am accustomed to wearing a wolf’s-head mask when I wish to avoid the attentions of photographers.’ A brief statement from the driver who had taken Duffield from Uzi confirmed Duffield’s account of visiting Kentigern Gardens and moving on to d’Arblay Street, where he had dropped his passenger and left. The antipathy Wardle claimed the driver had felt towards Duffield was not conveyed in the bald factual account prepared for his signature by the police.

There were a couple of other statements supporting Duffield’s: one from a woman who claimed to have seen him climbing the stairs to his dealer’s, one from the dealer, Whycliff, himself. Strike recalled Wardle’s expressed opinion that Whycliff would lie for Duffield. The woman downstairs could have been cut in on any payment. The rest of the witnesses who claimed to have seen Duffield roaming the streets of London could only honestly say that they had seen a man in a wolf mask.

Strike lit a cigarette and read through Duffield’s statement again. He was a man with a violent temper, who had admitted to attempting to force Lula to remain in the club. The bruising to the upper arms of the body was almost certainly his work. If, however, he had taken heroin with Whycliff, Strike knew that the odds of him being in a fit state to infiltrate number 18, Kentigern Gardens, or to work himself into a murderous rage, were negligible. Strike was familiar with the behaviour of heroin addicts; he had met plenty at the last squat his mother had lived in. The drug rendered its slaves passive and docile; the absolute antithesis of shouting, violent alcoholics, or twitchy, paranoid coke-users. Strike had known every kind of substance-abuser, both inside the army and out. The glorification of Duffield’s habit by the media disgusted him. There was no glamour in heroin. Strike’s mother had died on a filthy mattress in the corner of the room, and nobody had realised she was dead for six hours.