Riley faced the wall to her right and saw a hole in the brickwork. She stooped to examine it closely and noticed there was something lurking under the small mound of dust in the hole. With her index finger she scooped out the dust and encountered metal within the brick.

She felt the outline of a semi-circle on a metal base buried in the fabric of the wall.

Turning 180 degrees, she saw an identical hole at the same height on the wall with the door.

Riley considered the dimensions of the space in relation to the position of the graffiti and a bleak picture formed in her mind.

She took pictures of both holes and of the metal links sunk into the bricks.

Projecting the picture in her head into the space around her, the image became almost real, its details harrowing enough to make her run up the stairs two at a time.

In the kitchen she shouted, ‘Stop!’ The movement and noise in the house ceased. ‘Everyone in the hallway, ASAP. Now! Move! Please!’

As she called Clay on her iPhone, she noticed that her hand was shaking.

‘Did you get the picture I sent you, Eve?’

‘And, so, off she floats to nowhere? Have you been down in the basement?’

‘With a brand-new pair of eyes. I’m speculating but I’d gamble on it big time, Maguire and whoever she’s been collaborating with have had Annie Boyd and Amanda Winton captive together in the basement. Buried in the walls on the left- and right-hand side of the room are two metal links. They’re the first links in a pair of chains. They’ve had the two of them chained to the walls, staring at a vision of what was going to become of them. And, so, off she floats to nowhere.’

Officers gathered in the hall but no one uttered a word.

‘Norma Maguire knows if Francesca Christie’s still alive,’ said Clay. ‘She also knows, dead or alive, where she can be found.’

Riley looked at the silent officers and all eyes were on her.

‘Have we found anything of interest in the house?’ asked Riley.

Silence.

‘How many are we?’

She counted over a dozen bodies.

‘I want three to conduct a fingertip search of the first room in the basement and the wooden stairs leading down into it, and another three to do the same in the adjoining room. We’re combing the floor, walls and ceiling.’

Riley turned and walked back to the hatch, turning her iPhone on to video.

‘Do you want me to glue this together, DS Riley?’ asked the young constable as she passed his broken mosaic.

‘I would love you to make that piece of wall as permanent as you can, Tom.’

She hurried down the wooden steps and decided she would start with the place where the graffiti had been and work her way round the room in an anticlockwise direction.