'I just don't know how to proceed anymore. I've felt that way ever since we began this investigation. I went over everything again and again when I drove in to the station yesterday, but I've run out of ideas.'

'Is it true that nobody saw anything?'

He sighed. 'Yes, all they saw was Sara leaving the house. After that there was no trace of her. It's as if she vanished in a puff of smoke and then suddenly turned up in the sea.'

'I tried to ring Charlotte a while ago and Lilian answered,' Erica said cautiously. 'She sounded unusually curt, even for her. Is there something I should know about?'

Patrik hesitated, but finally decided to tell her. 'We did a crime- scene search at their house on Friday. Lilian was a bit upset about it…'

Erica raised her eyebrows. 'I can imagine. But why did you do that? I mean, someone outside the family must have done it, don't you think?'

Patrik shrugged. 'Yes, more than likely. But we can't just assume that's true. We have to investigate everything.' He was starting to get irritated that everyone was questioning the way he did his job. He couldn't rule out investigating the family simply because the idea was unpleasant. It was just as important to scrutinize the family members closely as it was to examine everything that pointed to an outside perpetrator. With no clues leading in a specific direction, all directions were equally important.

Erica could hear his irritation, and she patted him on the arm to show that she meant no offence. She felt him relax.

'Do we need to get something for dinner?' They were walking past the old clinic that was now a day-care centre, and saw the Konsum supermarket sign up ahead.

'Something good.'

'Do you mean dinner or dessert?' said Patrik, turning down the little hill towards the Konsum car park. Erica shot him a look, and Patrik laughed.

'Both,' she said. 'What I was thinking

When they emerged from the market with plenty of goodies loaded onto the pram's undercarriage, Patrik asked in surprise, 'Did I imagine it, or was the woman behind us in the queue giving me a funny look?'

'No, you weren't imagining it. That was Monica Wiberg, the Florins' neighbour. Her husband's name is Kaj and they have a son named Morgan, who I hear is a little strange.'

Now Patrik understood why the woman had been staring at him with such anger. Of course he wasn't the officer who had questioned her son, but it was probably enough that he was a member of the same profession.

'He has Asperger's,' said Patrik.

'Who?' said Erica, who had already forgotten what they were talking about and was fully engrossed in arranging Maja's cap, which had twisted to one side as she slept, exposing her ear to the autumn chill.

'Morgan Wiberg,' said Patrik. 'Gösta and Martin went over to talk to him, and he told them himself that he has something called Asperger's.'

'What's that?' said Erica curiously, letting Patrik push the pram once Maja's ears were both properly covered by the warm cap.

Patrik told her some of what he'd learned from Martin on Friday. It had been a good idea to go out and meet the psychologist.

'Is he a suspect?' Erica asked.

'No, not the way things look at the moment. But he seems to be the last person who saw Sara, so it doesn't hurt to know as much about him as possible.'

'To make sure that you're not targeting him because he's a little odd.' She bit her tongue as soon as she said that. 'Sorry, I know that you're more professional than that. It's just that in small towns like this, people who are different are always the ones singled out whenever something bad happens. Blame it on the village idiot, that sort of thing.'

'On the other hand, unusual individuals have always met with greater respect in small communities than in the big cities. An eccentric character is just another part of the daily scene and is accepted as he is. In the big city he would end up considerably more isolated.'

'You're right, but that kind of tolerance has always rested on shaky ground. That's all I'm saying.'

'Yeah, well, in any case Morgan isn't being treated any differently from anyone else, I can assure you of that.'

Erica didn't reply but stuck her arm under Patrik's again. The rest of the walk home they talked about other things. But she could sense that his thoughts were somewhere else the whole time.

By Monday the fine weather that had prevailed the day before was gone. Now it was just as grey and bitterly cold as before, and Patrik huddled up in a big, thick woollen jumper as he sat at his desk. Last summer the air conditioning hadn't worked, and it was like working in a sauna. Now the raw damp seeped through the walls, making him shiver. A ring from the telephone made him jump.

'You have a visitor,' Annika's voice said on the line.

'I'm not expecting anyone.'

'A Jeanette Lind says she wants to see you.'

Patrik pictured the curvaceous little brunette in his mind and wondered what she wanted.

'Send her in,' he said, getting up to greet his unexpected visitor. They shook hands politely in the corridor outside his office. Jeanette looked tired and haggard, and he wondered what had happened since last Friday when he last saw her. Many evening shifts at the restaurant, or something more personal?

'Would you like a cup of coffee?' he asked, and she nodded.

'Have a seat, and I'll bring you some.' He pointed to one of his guest chairs.

A moment later he set two cups on his desk.

'So, how can I help you?' He put his forearms on the desk and leaned forward.

It took a few seconds before she replied. With her eyes lowered, she warmed her hands on the coffee cup and seemed to be pondering how to begin. Then she tossed back her thick, dark hair and looked him straight in the eye.

'I lied about Niclas being with me last Monday,' she said.

Patrik's expression didn't reveal his consternation, but inside he felt something leap in his chest.

'Tell me more,' he said calmly.

'I just told you what Niclas had asked me to say. He gave me the times and asked me to say that we'd been together then.'

'And did he say why he wanted you to lie on his behalf?'

'All he said was that everything would be complicated otherwise. That it was much simpler for everyone if I gave him an alibi.'

'And you didn't question that?'

She shrugged. 'No, I had no reason to do so.'

'Even though a child had been murdered, you didn't think there was anything remarkable in him asking you to give him an alibi?' Patrik said incredulously.

Jeanette shrugged again. 'No,' she said. 'I mean, Niclas would hardly have killed his own daughter, would he?'

Patrik didn't reply. After a moment he asked, 'Niclas hasn't said anything about what he was actually doing that morning?'

'No.'

'And you have no idea yourself?'

Once again the impassive shrug of her shoulders. 'I just assumed he took the morning off. He works hard, and his wife is always nagging him about how he should help around the house, even though she's at home all day long. He probably needed a little free time.'

'And why would he risk his marriage by asking you to give him an alibi?' said Patrik, trying in vain to read something in Jeanette's aloof expression. The only thing that revealed any emotion was the way she was nervously drumming her long nails on the coffee cup.

'I have no idea,' she said impatiently. 'He probably thought that of two evils, it was better to be discovered with a lover than to be suspected of the murder of his own daughter.'

Patrik thought that sounded far-fetched, but people reacted strangely under stress; he'd seen many different examples.

'If you thought it was okay to give him an alibi as late as last Friday, why have you changed your mind now?'

Her nails kept drumming on the coffee cup. They were extremely well-manicured, even Patrik could see that.