Primarily, of course, they still had no idea who was carrying out these murders. Or why. Having misplaced the nearest thing they had to a prime suspect wasn’t exactly good news, either. John Mardell was still out there somewhere, having slipped their net during the raid, then managing to evade several police teams, who had spent the best part of three hours scouring Brentford for him. Her suspicions now were that he’d clambered over the wall in the confusion, and either chosen a direction on foot and just got lucky, or more likely picked up some form of public transport and been miles away before they’d even managed to deploy proper search teams. The worst part was that the supposedly sharp tools employed these days by the Met hadn’t been able to trace him in the ensuing ten hours.

Their best chance now was CCTV footage, and a much slower cornering of their target through wits and patience, rather than opportunism and surprise. The number of functioning cameras still aimed at the shabby town centre was likely to be low, and now the initial trail had gone cold, the search radius began to expand uncomfortably fast.

Her only other hope was that one of Mardell’s cronies, currently filling the cells at Southall station, might be convinced to give up some vital clue to his whereabouts.

But first she had business here.

Hawkins pushed herself away from the wall, and covered the final few feet to the open living room door. She stood at the threshold, her attention drawn immediately to the body lying face up in the centre of the floor. Once again, the profile fit: a twenty-something male in fashionable jeans, stripped to the waist, inert eyes staring upwards.

Not a mark on him.

There was a muted ping from behind her, and a few seconds later Aaron handed her his phone, its screen displaying the image of a driving licence.

‘Owns the Renault parked outside,’ he whispered.

Hawkins zoomed in on the photograph and lined it up with the dead man. The likeness, even from a distance, was undeniable. She flicked across to the name: Lewis Rudd had been twenty years old, and lived in Peckham, a few miles east of where they stood.

‘Send me that image, would you?’ She gave the phone to Aaron and turned her attention back to the scene, where a familiar mix of white overalls were circling the body, engaged in a slow, deliberate search for evidence. Hawkins knew one or two faces, but her focus was quickly drawn to the room. She glanced at her sergeant. ‘Looks like our killer is turning up his message.’

He stepped forwards and peered inside. ‘Shit.’

‘Exactly.’ She waited for him to move back and brought up her own mobile, taking several shots of the large symbols scrawled on each of the three walls visible from the doorway.