Her head lolls sideways and she can see that there's some old popcorn among the dust under the sofa.

Through the roaring sound inside her she can hear peculiar screams, and feels rapid stabs to her stomach and chest.

She tries to kick free, thinking to herself that she has to get back to the bathroom. The floor beneath her is slippery, and she has no energy left.

She tries to roll over on to her side, but the intruder grabs her by the chin and suddenly jabs the knife into her face. It no longer hurts. But a sense of unreality is spinning in her head. Shock and an abstract sense of dislocation blur with the precise and intimate feeling of being cut in the face.

The blade enters her neck and chest and face again. Her lips and cheeks fill with warmth and pain.

Susanna realises that she's not going to make it. Ice-cold anguish opens up like a chasm as she stops fighting for her life.

6.

Psychiatrist Erik Maria Bark is leaning back in his pale grey sheepskin armchair. He has a large study in his home, with a varnished oak floor and built-in bookcases. The dark brick villa is in the oldest part of Gamla Enskede, just to the south of Stockholm.

It's the middle of the day, but he was on call last night and could do with a few hours' sleep.

He shuts his eyes and thinks about when Benjamin was small and used to like to hear how Mummy and Daddy met. Erik would sit down on the edge of his bed and explain how Cupid, the G.o.d of love, really did exist.

He lived up amongst the clouds and looked like a chubby little boy with a bow and arrow in his hands.

'One summer's evening Cupid gazed down at Sweden and caught sight of me,' Erik explained to his son. 'I was at a university party, pushing my way through the crowd on the roof terrace when Cupid crept to the edge of his cloud and fired an arrow down towards the Earth.

'I was wandering about at the party, talking to friends, eating peanuts and exchanging a few words with the head of department.

'And at the exact moment that a woman with strawberry-blonde hair and a champagne gla.s.s in her hand looked in my direction, Cupid's arrow hit me in the heart.'

After almost twenty years of marriage Erik and Simone had agreed to separate, but she was probably the one who agreed the most.

As Erik leans forward to switch his reading-lamp off, he catches a glimpse of his tired face in the narrow mirror by the bookcase. The lines on his forehead and the furrows in his cheeks are deeper than ever. His dark-brown hair is flecked with grey. He ought to get a haircut. A few loose strands are hanging in front of his eyes and he flicks them away with a jerk of his head.

When Simone told him that she had met John, Erik realised it was over. Benjamin was pretty relaxed about the whole thing, and used to tease him by saying it would be cool to have two dads.

Benjamin is eighteen years old now, and lives in the big house in Stockholm with Simone and her new man, his stepbrothers and sisters, and the dogs.

On Erik's old smoking table is the latest edition of the American Journal of Psychiatry and a copy of Ovid's Metamorphoses, with a half-empty blister-pack of pills as a bookmark.

Outside the leaded windows the rain is falling on the drenched vegetation of the garden.

Erik pulls the tablets from the book and pops one sleeping-pill into his hand, trying to work out how long it would take his body to absorb the active substance, but he has to start again, then gives up. Just to be sure, he breaks the tablet in half along the little groove, blows the loose powder off to get rid of the bitter taste, then swallows one half.

The rain streams down the windows as the muted tones of John Coltrane's 'Dear Old Stockholm' flow from the speakers.

The tablet's chemical warmth spreads through his muscles. He shuts his eyes and enjoys the music.

Erik Maria Bark is a trained doctor, psychiatrist and psychotherapist, specialising in psychological trauma and disaster counselling, and worked for the Red Cross in Uganda for five years.

He spent four years leading a ground-breaking research project into group therapy involving deep hypnosis at the Karolinska Inst.i.tute. He is a member of the European Society of Hypnosis, and is regarded as a leading international authority on clinical hypnotherapy.

At the moment Erik is part of a small team specialising in acutely traumatised and post-traumatic patients. They are regularly called in to help the police and public prosecutors with complex interviews of crime victims.

He often uses hypnosis to help witnesses relax, so that they can get to grips with their memories of traumatic situations.

He's got three hours before he needs to be at a meeting at the Karolinska Inst.i.tute, and he's hoping to spend most of that time asleep.

But he's not allowed to.

He's dragged straight into deep sleep, and starts dreaming that he's carrying an old, bearded man through a very small house.

Simone is shouting at him from behind a closed door when the phone rings. Erik jumps, and fumbles for the smoking-table. His heart is beating hard from the sudden anxiety of being yanked out of a state of deep relaxation.

'Simone,' he answers groggily.

'h.e.l.lo, Simone ... I'm not sure, but maybe you should try to give up those French cigarettes?' Nelly jokes in her laconic way. 'Sorry to have to say this, but you almost sound like a man.'

'Almost.' Erik smiles, feeling the heaviness of the sleeping pill in his head.

Nelly laughs, a fresh, tinkling laugh.

Nelly Brandt is a psychologist, Erik's closest colleague in the specialist team at the Karolinska Hospital. She's extremely competent, works very hard, but is also very funny, often in a rather earthy way.

'The police are here, they're really agitated,' she says, and only now does he hear how stressed she sounds.

He rubs his eyes to get them to focus, and tries to listen to what Nelly is telling him about the police rushing in with an acutely shocked patient.

Erik squints towards the window facing the street, as water streams down the gla.s.s.

'We're checking his somatic status and running the routine tests,' she says. 'Blood and urine ... liver status, kidney and thyroid function ...'

'Good.'

'Erik, the superintendent has asked for you specifically ... It's my fault, I happened to let slip that you were the best.'

'Flattery doesn't work on me,' he says, getting to his feet somewhat unsteadily. He rubs his face with his hand, then grabs hold of the furniture as he makes his way towards the desk.

'You're standing up,' she says cheerily.

'Yes, but I ...'

'Then I'll tell the police that you're on your way.'

Beneath the desk are a pair of black socks with dusty soles, a long, thin taxi receipt and a mobile phone charger. As he bends over to grab the socks the floor comes rushing up to meet him, and he would have fallen if he hadn't put his hand out to stop himself.

The objects on the desk merge and spread out in double vision. The silver pens in their holder radiate harsh reflexions.

He reaches for a half-empty gla.s.s of water, takes a small sip and tells himself to get his act together.

7.

The Karolinska University Hospital is one of the largest in Europe, with more than fifteen thousand members of staff. The Psychology Clinic is located slightly apart from the vast hospital precinct. From above, the building looks like a Viking ship from an ancient burial site, but when approached through the park it doesn't look out of place among the other buildings. The nicotine-yellow stucco of the facade is still damp from the rain, with rust-coloured water running down the drainpipes. The front wheel of a bicycle is dangling from a chain in the bike-rack.

The car tyres crunch softly as Erik turns into the car park.

Nelly is standing on the steps waiting for him with two mugs of coffee. Erik can't help smiling when he sees her happy grin and the consciously disinterested look in her eyes.

Nelly is fairly tall, thin, and her bleached hair is always perfect, her make-up tasteful.

Erik often sees her and her husband Martin socially. There's no real need for Nelly to work, seeing as her husband is the main shareholder of Datametrix Nordic.

As she watches Erik's BMW pull into the car park she walks over to him, blowing on one of the mugs and taking a cautious sip before putting it on the roof of the car and opening the back door.

'I don't know what this is about, but we've got a superintendent who seems pretty wound up,' she says, pa.s.sing him one of the mugs between the seats.

'Thanks.'

'I explained that we always have the best interest of our patients at heart,' Nelly says as she gets in and closes the car door behind her. 's.h.i.t! G.o.d, sorry ... have you got any tissues? I've spilled some coffee on the seat.'

'Don't worry.'

'Are you cross? You're cross,' she says.

The smell of coffee spreads through the car and Erik closes his eyes for a moment.

'Nelly, just tell me what they said.'

'I don't seem to be getting on very well with that f.u.c.king ... I mean, that lovely policewoman.'

'Is there anything I ought to know before I go inside?' he asks, opening the door.

'I told her she could wait in your office and go through your drawers.'

'Thanks for the coffee ... both mugs,' he says, as they get out of the car.

Erik locks up, puts the keys in his pocket, runs a hand through his hair and starts to walk towards the clinic.

'I didn't actually say that bit about the drawers,' she calls after him.

Erik walks up the steps, turns right and runs his pa.s.scard through the reader, taps in his code, then carries on along the next corridor to his room. He still feels groggy, and it occurs to him that he really must get the tablets under control soon. They make him sleep too deeply. It's almost like drowning. His drugged dreams have started to feel claustrophobic. Yesterday he had a nightmare about two dogs that had grown into each other, and last week he fell asleep here at the clinic and had a s.e.xual dream about Nelly. He can't really remember it, but she was on her knees in front of him handing him a cold, gla.s.s ball.

His thoughts dissipate when he sees the superintendent sitting on his office chair with her feet resting on the edge of the waste-paper bin. She's holding her huge stomach with one hand and a can of c.o.ke in the other. Her brow is furrowed, her chin has fallen open and she's breathing through her half-open mouth.

Her ID badge is lying on his desk, and she gestures wearily towards it as she introduces herself.

'Margot Silverman ... National Crime.'

'Erik Maria Bark,' he says, shaking her hand.

'Thanks for coming in at such short notice,' she says, moistening her lips. 'We've got a traumatised witness ... Everyone tells me I should have you in the room with me. We've already tried to question him four times ...'

'I have to point out that there are five of us here in our specialist unit, and that I never usually sit in on interviews of perpetrators or suspected perpetrators myself.'

The light from the ceiling lamp reflects off her pale eyes. Her curly hair is trying to escape from her thick plait.

'OK, but Bjrn Kern isn't a suspect. He works in London, and was on a plane home when someone murdered his wife,' she replies, squeezing the c.o.ke-can and making the thin metal creak.

'OK, then,' Erik says.

'He got a taxi from Arlanda, and found her dead,' the superintendent goes on. 'We don't know exactly what he did after that, but he was certainly busy. We're not sure where she was lying to start with, we found her tucked up in bed in the bedroom ... He cleaned up as well, wiped away the blood ... he doesn't remember anything, he says, but the furniture had been moved, and the blood-soaked rug was already in the washing machine ... he was found more than a kilometre away from the house, a neighbour almost ran him over on the road, he was still wearing his blood-soaked suit, no shoes.'

'I'll certainly see him,' Erik says. 'But I must say at the outset that it would be wrong to try to force information from him.'

'He has to talk,' she says stubbornly, squeezing the can tighter.

'I understand your frustration, but he could enter a psychosis if you push too hard ... Give him time, he'll tell you what you need.'

'You've helped the police before, haven't you?'

'Many times.'

'But this time ... this is the second murder in what looks like a series,' she says.

'A series,' Erik repeats.

Margot's face has turned grey and the thin lines round her eyes are emphasised by the light from the lamp.

'We're hunting a serial killer.'

'OK, I get that, but the patient needs-'

'This murderer has entered an active phase, and isn't going to stop of his own accord,' she interrupts. 'And Bjrn Kern is a disaster from my point of view. First he goes round and rearranges everything at the crime scene before the police get there ... and now we can't get him to tell us what it looked like when he arrived.'

She drops her feet to the floor, whispers to herself that they need to get going, then sits there stiff-backed, panting for breath.