They had detained the husband on the staircase while the woman was questioned. No, she did not want to file a police report. No, it was all a mistake. No, he was fine... it was actually all her fault. She had provoked him...

And the whole time the bastard had stood there grinning, looking Linder straight in the eye.

She could not explain why she did it. But suddenly something had snapped in her, and she took out her baton and slammed it across his face. The first blow had lacked power. She had only given him a fat lip and forced him on to his knees. In the next ten seconds  -  until her colleagues grabbed her and half dragged, half carried her out of the halfway  -  she had let the blows rain down on his back, kidneys, hips and shoulders.

Charges were never filed. She had resigned the same evening and went home and cried for a week. Then she pulled herself together and went to see Dragan Armansky. She explained what she had done and why she had left the force. She was looking for a job. Armansky had been sceptical and said he would need some time to think it over. She had given up hope by the time he called six weeks later and told her he was ready to take her on trial.

Linder frowned and stuck the baton into her belt at the small of her back. She checked that she had the Mace canister in her right-hand pocket and that the laces of her trainers were securely tied. She walked back to Berger's house and slipped into the garden.

She knew that the outside motion detector had not yet been installed, and she moved soundlessly across the lawn, along the hedge at the border of the property. She could not see him. She went around the house and stood still. Then she spotted him as a shadow in the darkness near Beckman's studio.

He can't know how stupid it is for him to come back here.

He was squatting down, trying to see through a gap in a curtain in the room next to the living room. Then he moved up on to the veranda and looked through the cracks in the drawn blinds at the big picture window.

Linder suddenly smiled.

She crossed the lawn to the corner of the house while he still had his back to her. She crouched behind some currant bushes by the gable end and waited. She could see him through the branches. From his position Fredriksson would be able to look down the hall and into part of the kitchen. Apparently he had found something interesting to look at, and it was ten minutes before he moved again. This time he came closer to Linder.

As he rounded the corner and passed her, she stood up and spoke in a low voice:

"Hello there, Fredriksson."

He stopped short and spun towards her.

She saw his eyes glistening in the dark. She could not see his expression, but she could hear that he was holding his breath and she could sense his shock.

"We can do this the easy way or we can do it the hard way," she said. "We're going to walk to your car and  - "

He turned and made to run away.

Linder raised her baton and directed a devastatingly painful blow to his left kneecap.

He fell with a moan.

She raised the baton a second time, but then caught herself. She thought she could feel Armansky's eyes on the back of her neck.

She bent down, flipped him over on to his stomach and put her knee in the small of his back. She took hold of his right hand and twisted it round on to his back and handcuffed him. He was frail and he put up no resistance.

Berger turned off the lamp in the living room and limped upstairs. She no longer needed the crutches, but the sole of her foot still hurt when she put any weight on it. Beckman turned off the light in the kitchen and followed his wife upstairs. He had never before seen her so unhappy. Nothing he said could soothe her or alleviate the anxiety she was feeling.

She got undressed, crept into bed and turned her back to him.

"It's not your fault, Greger," she said when she heard him get in beside her.

"You're not well," he said. "I want you to stay at home for a few days."

He put an arm around her shoulders. She did not to push him away, but she was completely passive. He bent over, kissed her cautiously on the neck, and held her.

"There's nothing you can say or do to make the situation any better. I know I need to take a break. I feel as though I've climbed on to an express train and discovered that I'm on the wrong track."

"We could go sailing for a few days. Get away from it all."

"No. I can't get away from it all."

She turned to him. "The worst thing I could do now would be to run away. I have to sort things out first. Then we can go."

"O.K," Beckman said. "I'm not being much help."

She smiled wanly. "No, you're not. But thanks for being here. I love you insanely  -  you know that."

He mumbled something inaudible.

"I simply can't believe it's Fredriksson," Berger said. "I've never felt the least bit of hostility from him."

Linder was just wondering whether she should ring Berger's doorbell when she saw the lights go off on the ground floor. She looked down at Fredriksson. He had not said a word. He was quite still. She thought for a long time before she made up her mind.

She bent down and grabbed the handcuffs, pulled him to his feet, and leaned him against the wall.

"Can you stand by yourself?" she said.

He did not answer.

"Right, we'll make this easy. You struggle in any way and you'll get the same treatment on your right leg. You struggle even more and I'll break your arms. Do you understand?"

She could hear him breathing heavily. Fear?

She pushed him along in front of her out on to the street all the way to his car. He was limping badly so she held him up. Just as they reached the car they met a man out walking his dog. The man stopped and looked at Fredriksson in his handcuffs.

"This is a police matter," Linder said in a firm voice. "You go home." The man turned and walked away in the direction he had come.

She put Fredriksson in the back seat and drove him home to Fisksatra. It was 12.30 and they saw no-one as they walked into his building. Linder fished out his keys and followed him up the stairs to his apartment on the fourth floor.

"You can't go into my apartment," said Fredriksson.

It was the first thing he had said since she cuffed him. She opened the apartment door and shoved him inside.

"You have no right. You have to have a search warrant  - "

"I'm not a police officer," she said in a low voice.

He stared at her suspiciously.

She took hold of his shirt and dragged him into the living room, pushing him down on to a sofa. He had a neatly kept two-bedroom apartment. Bedroom to the left of the living room, kitchen across the hall, a small office off the living room.

She looked in the office and heaved a sigh of relief. The smoking gun. Straightaway she saw photographs from Berger's album spread out on a desk next to a computer. He had pinned up thirty or so pictures on the wall behind the computer. She regarded the exhibition with raised eyebrows. Berger was a fine-looking woman. And her sex life was more active than Linder's own.

She heard Fredriksson moving and went back to the living room, rapped him once across his lower back and then dragged him into the office and sat him down on the floor.

"You stay there," she said.

She went into the kitchen and found a paper carrier bag from Konsum. She took down one picture after another and then found the stripped album and Berger's diaries.

"Where's the video?" she said.

Fredriksson did not answer. Linder went into the living room and turned on the T.V. There was a tape in the V.C.R., but it took a while before she found the video channel on the remote so she could check it. She popped out the video and looked around to ensure he had not made any copies.

She found Berger's teenage love letters and the Borgsjo folder. Then she turned her attentions to Fredriksson's computer. She saw that he had a Microtek scanner hooked up to his P.C., and when she lifted the lid she found a photograph of Berger at a Club Xtreme party, New Year's Eve 1986 according to a banner on the wall.

She booted up the computer and discovered that it was password-protected.

"What's your password," she asked.

Fredriksson sat obstinately silent and refused to answer.

Linder suddenly felt utterly calm. She knew that technically she had committed one crime after another this evening, including unlawful restraint and even aggravated kidnapping. She did not care. On the contrary, she felt almost exhilarated.

After a while she shrugged and dug in her pocket for her Swiss Army knife. She unplugged all the cables from the computer, turned it round and used the screwdriver to open the back. It took her fifteen minutes to take it apart and remove the hard drive.

She had taken everything, but for safety's sake she did a thorough search of the desk drawers, the stacks of paper and the shelves. Suddenly her gaze fell on an old school yearbook lying on the windowsill. She saw that it was from Djurholm Gymnasium 1978. Did Berger not come from Djurholm's upper class? She opened the yearbook and began to look through that year's school leavers.

She found Erika Berger, eighteen years old, with student cap and a sunny smile with dimples. She wore a thin, white cotton dress and held a bouquet of flowers in her hand. She looked the epitome of an innocent teenager with top grades.

Linder almost missed the connection, but there it was on the next page. She would never have recognized him but for the caption. Peter Fredriksson. He was in a different class from Berger. Linder studied the photograph of a thin boy in a student cap who looked into the camera with a serious expression.

Her eyes met Fredriksson's.

"Even then she was a whore."

"Fascinating," Linder said.

"She fucked every guy in the school."

"I doubt that."

"She was a fucking  - "

"Don't say it. So what happened? Couldn't you get into her knickers?"

"She treated me as though I didn't exist. She laughed at me. And when she started at S.M.P. she didn't even recognize me."

"Right," said Linder wearily. "I'm sure you had a terrible childhood. How about we have a serious talk?"

"What do you want?"

"I'm not a police officer," Linder said. "I'm someone who takes care of people like you."

She paused and let his imagination do the work.

"I want to know if you put photographs of her anywhere on the Internet."

He shook his head.

"Are you quite sure about that?"

He nodded.

"Berger will have to decide for herself whether she wants to make a formal complaint against you for harassment, threats, and breaking and entering, or whether she wants to settle things amicably."

He said nothing.

"If she decides to ignore you  -  and I think that's about what you're worth  -  then I'll be keeping an eye on you."

She held up her baton.

"If you ever go near her house again, or send her email or otherwise molest her, I'll be back. I'll beat you so hard so that even your own mother won't recognize you. Do I make myself clear?"

Still he said nothing.

"So you have the opportunity to influence how this story ends. Are you interested?"

He nodded slowly.

"In that case, I'm going to recommend to Fru Berger that she lets you off, but don't think about coming into work again. As of right now you're fired."

He nodded.

"You will disappear from her life and move out of Stockholm. I don't give a shit what you do with your life or where you end up. Find a job in Goteborg or Malmo. Go on sick leave again. Do whatever you like. But leave Berger in peace. Are we agreed?"

Fredriksson began to sob.

"I didn't mean any harm," he said. "I just wanted  - "

"You just wanted to make her life a living hell and you certainly succeeded. Do I or do I not have your word?"

He nodded.

She bent over, turned him on to his stomach and unlocked the handcuffs. She took the Konsum bag containing Berger's life and left him there on the floor.

It was 2.30 a.m. on Monday when Linder left Fredriksson's building. She considered letting the matter rest until the next day, but then it occurred to her that if she had been the one involved, she would have wanted to know straightaway. Besides, her car was still parked out in Saltsjobaden. She called a taxi.

Beckman opened the door even before she managed to ring the bell. He was wearing jeans and did not look as if he had just got out of bed.

"Is Erika awake?" Linder asked.

He nodded.

"Has something else happened?" he said.

She smiled at him.

"Come in. We're just talking in the kitchen."

They went in.

"Hello, Erika," Linder said. "You need to learn to get some sleep once in a while."

"What's happened?"

Linder held out the Konsum bag.

"Fredriksson promises to leave you alone from now on. God knows if we can trust him, but if he keeps his word it'll be less painful than hassling with a police report and a trial. It's up to you."

"So it was him?"

Linder nodded. Beckman poured a coffee, but she did not want one. She had drunk much too much coffee over the past few days. She sat down and told them what had happened outside their house that night.

Berger sat in silence for a moment. Then she went upstairs, and came back with her copy of the school yearbook. She looked at Fredriksson's face for a long time.

"I do remember him," she said at last. "But I had no idea it was the same Peter Fredriksson. I wouldn't even have remembered his name if it weren't written here."