‘Got it.’ He held still as Hawkins grabbed the top of the wall, relieved to find no glass or barbed wire, and pulled herself up far enough to see over into the enclosed space. Thankfully, the tree in front of her still had its leaves, blocking the view in or out of the main building, the corner of which Hawkins could just make out through the lower branches. She couldn’t see any windows, but an amber glow was escaping on to the ground from somewhere inside, flickering in a way that meant only one thing.

Fire.

For a moment, she considered dropping back down and simply calling the fire brigade. But the disorder of such an intervention might prevent her from finding out what was going on, and that information could be critical to the investigation.

She needed to see for herself.

Hawkins levered herself up on to the narrow surface, twisting so that she was lying face down along the top edge of the wall. She scanned the shadows below, seeing a dozen or so wooden pallets stacked against the wall, next to some rusting steel girders. But the gap between them was large enough for her to drop into.

She glanced back at Aaron and motioned towards the car with her chin. He nodded and moved away as Hawkins shuffled around, hung her legs over the edge and dropped to arms’ length before letting go, to fall the last couple of feet to the ground, tensing as her foot caught the edge of a pallet, making it bang against its neighbour. She dropped into a crouch and held her position, alert for signs that anyone had heard her arrival.

Nothing happened.

Hawkins scoured the darkness around her. She was in a narrow thoroughfare between the back of the structure and the perimeter wall. Beyond the building, she could see a few cars parked together, and to the right, flame-red patterns still danced on the concrete floor, increasing her chances of being seen if she ventured that way. But to her left the walkway seemed to keep going around the building, disappearing into darkness, which meant there were no ground-level windows on that side.

Hawkins stood and went to the corner, using the light on her phone to see. There, she backed up against the corrugated metal, feeling its rough finish rasp against her coat. She paused to listen for movement.

Hearing nothing, she leaned out and peered into the adjoining alley, which ran the length of the building. A single street lamp illuminated the far end of a pathway almost blocked by tangled undergrowth. But her attention was drawn to a rusting metal staircase that started a few yards in. A fire escape. Her eyes followed it to the top, where a dull glow was escaping from a short row of windows high in the structure.

Her chance to see what was happening inside.