Lydia’s body was stretched out behind the sofa. She lay on her back, arms flung out at her sides. There were sticky patches of blood on the side of her head and smears at head height on the flecked wallpaper. A syringe sagged in her shoulder, the skin surrounding it already turning black from necrosis. Lydia’s T-shirt had risen up across her stomach and they saw blue-purple discolouration around her sides where livor mortis had set in, the blood settling in the lower part of her body after her heart stopped pumping.

‘There’s a spoon in the sink with a scorch mark beneath it,’ said Ajay. ‘And open drawers and cabinets. The contents look disturbed. Someone could have been searching the flat for something, of course, but Lydia doesn’t strike me as the tidiest of people.’

Sasha knew the spoon would have been used to liquefy the heroin injected into Lydia’s arm. She heard forensic staff place tubs of equipment on the balcony ready to get to work, and told officers inside the flat to be thorough in their search. They could find evidence of the identity of Lydia’s boyfriend, Matt Foster, the man Karin had identified as Lucas’s abductor – fingerprints, forensic material, maybe even an address scribbled on a scrap of paper – but she somehow doubted it.

She and Ajay crouched near Lydia’s body on the brown diamond-patterned carpet. ‘Poor woman.’

Sasha considered whether yesterday’s pursuit of her mysterious boyfriend, and his possible involvement in the abductions of Sammi and Lucas, had tipped Lydia back into drug use – and an overdose.

‘It could be accidental,’ said Ajay, playing devil’s advocate, ‘or she tripped and hit her head on the wall in a stupor, or intended to overdose.’

‘Any of those could well be the case.’ Sasha pointed at the position of the syringe. ‘But never in all my years have I known an experienced user to inject into muscle tissue before. We need a post-mortem ASAP, Ajay. This afternoon, if possible.’

‘On it,’ he said.

Sasha said, ‘Now be so kind as to point me in the direction of Karin.’

Leaning against the door of a police van, Karin straightened as Sasha approached. ‘I don’t understand how this could have happened. Lydia was clean, she hasn’t touched drugs for almost two years. If she was using again, I would have known, she would have come to me for help.’

‘We’ll need to wait for the results of the post-mortem before we can rush to judgement, but at this stage we’re treating Lydia’s death as suspicious.’

‘Suspicious?’ Karin stared. ‘You mean it wasn’t an overdose? Was it the man who took Lucas? Did he kill her in revenge, Matt whoever he is?’

‘Why would he do that?’ asked Sasha, interested.

‘I don’t know, for what happened yesterday.’ Karin looked in shock. ‘I just don’t understand why she would be murdered.’