They start walking and hear a muffled scream through the walls.
A bloody sanitary towel has been dumped on the floor, along with a few long strips of toilet paper.
They are approaching a door that has been left ajar, and pale light spills out into the corridor through the gap.
Somewhere up ahead, a man with a deep voice shouts aggressively.
Joona slowly moves over to the doorway and peers into the small control room on the other side. There is no sign of anyone, but he notices a thin column of smoke curling up towards the ceiling from the cigarette in the ashtray, and the large computer monitor is displaying eight livestreams.
Through a grubby window, he can see a studio containing a number of booths fitted with webcams.
In one, a naked boy with a look of apathy on his face is sitting in a pool of blood on a workout bench. His skinny body is covered in bruises, old and new.
‘God,’ Stina whispers, taking out her phone.
A large man with a tattooed face steps forward and holds a gun to the boy’s head as another man starts hitting him on the thigh with a long, thin dildo.
The two detectives continue past the control room as Stina quietly calls command to explain the situation and emphasises that it is urgent.
‘Ten minutes. They’ll be here in ten minutes,’ she tells Joona.
They pass the dented steel door to the studio and a smallcloakroom cluttered with trainers, clothes and bags.
The corridor is dark.
Behind them, they hear raised voices.
Against one wall, there are a number of empty wine bottles and a car battery.
Joona meets Stina’s eye. She looks frightened.
The next door is propped open, with a rolled newspaper wedged above the bottom hinges.
Joona pops his head inside.
A naked lightbulb illuminates a room with a carpet covered in rubbish, old popcorn and a pair of broken glasses.
Olga is sitting beside a young man on the stained denim sofa.
She is wearing a tight-fitting silver dress and heels, eating salad from a small red tub.
In a flat tone of voice, she tells the young man that everything will be fine, that he will be able to send money home.
Olga glances up at Joona with a spaced-out look on her face. The skin around one of her eyes is bruised and swollen, and her dark roots are showing through her dyed blonde hair.
With her free hand, she reaches up to wipe her mouth.
‘Olga,’ Joona says as he strides over to her. ‘We’re from the police, we need—’
‘Joona!’ Stina shouts.
A stocky man in a pair of sliders, tracksuit bottoms and a sweaty basketball vest straining over his rounded belly has burst into the room and stabbed her in the back.
Joona snatches the fork from the carton in Olga’s hand and swings around. He drives it into the man’s throat, pulls it out and hits him again.
Blood sprays across the man’s hairy shoulders.
He lets go of the knife, sways unsteadily, and crashes into the floor lamp.