'If we put pressure on him now, he may clam up for good,' Erik says, unlocking his birchwood cabinet and removing the fake-leather case containing his camera.

She gets to her feet, puts the can down on the desk at last, picks up her badge and walks heavily towards the door.

'Obviously I realise that this is seriously b.l.o.o.d.y awful for him, given what's happened, but he's going to have to pull himself together and-'

'Yes, but it's a lot more than awful ... it might actually be impossible for him to think about it at the moment,' Erik replies. 'Because what you've described sounds like a critical stress response, and-'

'Those are just words,' she interrupts, her cheeks flushing with irritation.

'A mental trauma can be followed by an acute blockage-'

'Why? I don't believe that,' she says.

'As you may know, our spatial and temporal memories are organised by the hippocampus ... and that information is then conveyed to the prefrontal cortex,' Erik replies patiently, pointing to his forehead. 'But that all changes at times of extreme arousal, and in cases of shock ... When the amygdala identifies a threat, both the autonomous nervous system and what's known as the cortisol axis are activated, and-'

'OK, what the h.e.l.l, I get it. Loads of stuff happens in the brain.'

'The important thing is that this degree of stress means that memories aren't stored as they usually are, but at an effective distance ... they're frozen, like ice-cubes, separately ... closed off.'

'I get it, you're saying he's doing his best,' Margot says, putting her hand on her stomach. 'But Bjrn may have seen something that can help us stop this serial killer. You have to get him to calm down, so he starts talking.'

'I will, but I can't tell you how long that's going to take,' he replies. 'I've worked in Uganda with people who've suffered the trauma of war ... people whose lives have been completely shattered. You have to move slowly, using security, sleep, conversation, exercise, medication-'

'Not hypnosis?' she asks, with an involuntary smile.

'Sure, as long as no one has exaggerated expectations about the result ... Sometimes gentle hypnosis can help a patient to restructure their memories so that they can actually be accessed.'

'Right now I'd give the go-ahead for a horse to kick him in the head if that would help.'

'OK, but that's a different department,' Erik says drily.

'Sorry, I get a bit impatient when I'm pregnant,' she says, and he can hear how hard she's trying to sound reasonable. 'But I have to identify any parallels with the first murder, I need a pattern if I'm going to be able to track down this murderer, and right now I haven't got a thing.'

They've reached the patient's room. Two uniformed police officers are standing outside the door.

'This is important to you,' Erik says. 'But bear in mind that he's just found his wife murdered.'

8.

Erik follows Margot into the room. It has been furnished with two armchairs and a sofa, a low white table, two chairs, a water dispenser with plastic cups, and a wastepaper bin.

On the floor under the windowsill is a broken pot, the linoleum floor strewn with soil.

The air is thick with stress and sweat. The man is standing in the far corner, as if he were trying to get as far away as possible.

When he sees Erik and Margot he slides towards the sofa with his back against the wall. He's extremely pale, with a hunted look in his bloodshot eyes. His pale blue shirt has sweat rings under the arms, and is hanging outside his trousers.

'h.e.l.lo, Bjrn,' Margot says. 'This is Erik, he's a doctor here.'

The man looks anxiously at Erik, then moves back into the corner.

'h.e.l.lo,' Erik says.

'I'm not ill.'

'No, but what you've been through means that you have the right to treatment,' Erik replies matter-of-factly.

'You don't know what I've been through,' the man says, then whispers something to himself.

'I know you haven't been given any tranquillisers,' Erik says calmly. 'But I'd like you to know that the option is there, if-'

'What the f.u.c.k do I want a load of pills for?' he b.u.t.ts in. 'Will pills help? Will they make everything all right?'

'No, but-'

'Will they let me see Sanna again?' he shouts. 'That's not going to happen is it?'

'Nothing can change what's happened,' Erik says seriously. 'But your relationship to what has happened will change, regardless of whether you-'

'I don't even understand what you're saying.'

'I'm just trying to find a good way to explain that the way you're feeling is part of a process, and that you can accept my help with that process if you want to.'

Bjrn glances at him briefly, then slips further away along the wall.

Margot puts her little recording device on the table, babbles the date and time, and the names of those present in the room.

'This is the fifth interview with Bjrn Kern,' she concludes, then turns towards him as he stands picking at the back-rest of the sofa. 'Bjrn, can you tell me in your own words-'

'About what?' he asks quickly. 'About what?'

'About when you got home,' Margot replies.

'What for?' he whispers.

'Because I want to know what happened, and what you saw,' she says curtly.

'What do you mean? I just got home, isn't that allowed?'

He puts his hands over his ears and stands there panting. Erik notes that the knuckles of both his hands are bleeding.

'What did you see?' Margot asks wearily.

'Why are you asking me that? I don't know why you're asking me. f.u.c.king h.e.l.l ...'

Bjrn shakes his head and rubs his mouth and eyes hard.

'I want you to feel safe here, in this room,' Erik says. 'You don't think you're allowed to relax, you might not think it's possible, but it is.'

The man picks at the edge of a piece of wallpaper with his fingernails, then tears off a little strip.

'This is what I'm thinking,' he says, without looking at them. 'I'm thinking I've got to do it all again, but do it right this time ... I've got to go home and go in through the door, and then it will be right.'

'How do you mean, right?' Erik asks, managing to catch his eye.

'I know how it sounds, but what if it's true, you can't know,' he says, making a despairing gesture to keep them quiet. 'I can go in, through the door, and call Sanna's name ... She knows I've got something for her, I always have, something from duty-free ... and I take my shoes off and go inside ...'

He looks utterly distraught.

'There's soil on the floor,' he whispers.

'Was there soil on the floor?' Margot asks.

'Shut up!' Bjrn yells, his voice cracking.

He walks over the soil-strewn floor, picks up the other pot-plant and throws it at the wall. The plastic pot shatters and soil rains down behind the sofa.

'f.u.c.king h.e.l.l!' he gasps.

He leans both hands against the wall, his head hanging, and a string of saliva drops to the floor.

'Bjrn?'

'f.u.c.k it, this is hopeless,' he says, with a sob in his voice.

'Bjrn,' Erik says slowly. 'Margot is here to find out more about what happened. That's her job. My job is to help you. I'm here for your sake ... I'm used to seeing people who are having trouble, people who have suffered a terrible loss, who've experienced terrible things ... things no one should have to go through, but which unfortunately are part of life for some of us.'

The man doesn't respond. He just sobs quietly. His eyes are dark, bloodshot and gla.s.sy.

'Do you want to stand over there?' Erik asks gently. 'You wouldn't rather sit in the armchair?'

'I don't care.'

'Nor do I ...'

'Good,' Bjrn whispers, turning towards him.

'I've already mentioned it, and I know what you said, but it's my job to offer you all the help that's available ... I can give you a sedative. It won't get rid of the terrible thing that's happened, but it will help to calm the panic you're feeling inside.'

'Can you help me?' the man whispers after a pause.

'I can help you take the first steps towards ... towards getting through the worst of it,' Erik explains quietly.

'I start to shake when I think about the front door at home ... because I must have gone through a different door, the wrong door.'

'I can understand why you'd feel that.'

Bjrn moves his lips cautiously, as though they were hurting him.

'Do you want me to sit down?' he asks, glancing cautiously at Erik.

'If it would make you feel more comfortable,' Erik replies.

Bjrn sits down for the first time, and Erik notices Margot looking at him, but doesn't return the look.

'What happens when you walk through the wrong door?'

'I don't want to think about it,' he replies.

'But you do remember?'

'Can you ... can you get rid of the panic?' the man whispers to Erik.

'That's your decision,' Erik says. 'But I'm happy to sit here and talk to you with Margot ... or you and I could talk on our own ... and we could also try hypnosis that might help you through the worst of it.'

'Hypnosis?'

'Some people find it works well,' Erik replies simply.

'No.' Bjrn smiles.

'Hypnosis is just a combination of relaxation and concentration.'

Bjrn laughs silently with his hand over his mouth, then stands up and walks along the wall again until he reaches the corner and turns to look at Erik.

'I think maybe the drugs you mentioned might be a good idea ...'

'OK.' Erik nods. 'I can give you Stesolid have you heard of that before? It will make you feel warm and tired, but also a lot calmer.'

'OK, good.'

Bjrn slaps the wall several times with one palm, then walks over to the water dispenser.

'I'll ask a nurse to bring you the pill,' Erik says.

He leaves the room, confident that Bjrn Kern will request hypnosis fairly soon.