“He’s one of our leading scientists,” she repeated, through clenched teeth.

“He keeps the brain of a 4-year-old girl on his mantelpiece!” Erlendur shouted.

“I don’t expect you to understand scientific work,” she said.

“What is there to understand about this?”

“I should never have let you in here,” Hanna shouted.

“I’ve heard that one before,” Erlendur said.

Elinborg found the woman from Husavik.

She had two remaining names on her list so she left Sigurdur Oli behind in Nordurmyri with the forensic team. The first woman’s reaction was a familiar one, great but somehow predetermined surprise, she’d heard the story elsewhere, even several times. She said that to tell the truth she’d been expecting the police. The second woman, the last one on Elinborg’s list, refused to talk to her. Refused to let her in. Closed the door saying she didn’t know what Elinborg was talking about and couldn’t help her.

But the woman was somehow hesitant. It was as if she needed to summon up all the strength she could muster to say what she wanted and Elinborg felt the role was rehearsed. She behaved as if she’d been expecting the police, but, unlike the others, she didn’t want to know anything. Wanted to get rid of Elinborg immediately.

Elinborg could tell she’d found the woman they’d been looking for. She took another look at her documents. The woman’s name was Katrin and she was a department manager at Reykjavik City Library. Her husband was the manager of a large advertising agency. She was 60. Three children, all born from 1958 to 1962. She’d moved from Husavik in ’62 and had lived in Reykjavik ever since.

Elinborg rang the bell a second time.

“I think you ought to talk to me,” she said when Katrin opened the door again.

The woman looked at her.

“There’s nothing I can help you with,” she said at once, in a surprisingly sharp tone of voice. “I know what the case is about. I’ve heard the rumours. But I don’t know about any rape. Hopefully you’ll make do with that. Don’t disturb me again.”

She tried to close the door on Elinborg.

“I may make do with that but a detective called Erlendur, who’s investigating Holberg’s murder, won’t. The next time you open the door he’ll be standing here and he won’t leave. He won’t let you slam the door in his face. He could have you brought down the station if things get difficult.”

“Will you please leave me alone,” Katrin said as the door shut against the frame.

I wish I could, Elinborg thought. She took out her mobile phone and called Erlendur, who was just leaving the university. Elinborg described the situation to him. He said he’d be there in ten minutes.

He couldn’t see Elinborg anywhere outside Katrin’s house when he arrived, but he recognised her car in the parking space. It was a large detached house in Vogar district, two storeys with a double garage. He rang the bell and to his astonishment Elinborg answered the door.

“I think I’ve found her,” she said in a low voice and let Erlendur in. “She came out to me just now and apologised for her behaviour. She said she’d rather talk to us here than down the station. She’d heard stories about the rape and she was expecting us.”

Elinborg went inside the house ahead of Erlendur and into the sitting room where Katrin was standing. She shook his hand and tried to smile, but didn’t make a very good job of it. She was conservatively dressed, wearing a grey skirt and white blouse, with straight, thick hair down to her shoulders, combed to one side. She was tall, with thin legs and small shoulders, pretty with a mild but anxious expression.

Erlendur looked around in the sitting room. It was dominated by books shelved in closed, glass-fronted cupboards. A beautiful writing desk stood by one of the book cupboards, an old but well-preserved leather suite was in the middle of the room, a smoking table in one corner. Paintings on the walls. Little watercolours in beautiful frames, photographs of her family. He took a closer look at them. All the photographs were old. The three boys with their parents. The most recent ones had been taken when they were confirmed. They did not seem to have graduated from school or university, or got married.

“We’re going to buy a smaller place,” Katrin said almost apologetically when she saw Erlendur looking around. “It’s far too big for us, this huge house.”

Erlendur nodded.

“Your husband, is he at home too?”

“Albert won’t be home until late tonight. He’s abroad. I was hoping we could talk about this before he gets back.”

“Shouldn’t we sit down?” Elinborg asked. Katrin apologised for her rudeness and invited them to sit down. She sat down on the sofa by herself, with Erlendur and Elinborg in the two leather armchairs facing her.

“What exactly is it you want of me?” Katrin asked, looking at them each in turn. “I don’t really understand how I fit into the picture. The man’s dead. That’s nothing to do with me.”

“Holberg was a rapist,” Erlendur said. “He raped a woman in Keflavik and, as a result, she had a child. A daughter. When we starting checking more closely we were told he’d done this before, to a woman from Husavik, a similar age to the second victim. Holberg may have raped again, later. We don’t know. But we need to track down his victim from Husavik. Holberg was murdered at his home and we have reason to presume that the explanation may be found in his sordid past.”

Erlendur and Elinborg both noticed how his speech didn’t seem to have any effect on Katrin. She wasn’t shocked at hearing about Holberg’s rapes or his daughter, and she asked neither about the woman from Keflavik nor the girl.

“You’re not shocked to hear that?” he said.

“No,” Katrin said, “what should I be shocked about?”

“What can you tell us about Holberg?” Erlendur asked after a pause.

“I recognised him at once from the photos in the papers,” Katrin said, and it was as if the last trace of resistance vanished from her voice. Her words turned into a whisper. “Even though he’d changed a lot,” she said.

“We had his photograph on file,” Elinborg said by way of explanation. “The photo was from an HGV licence he had recently renewed. Lorry driver. Drove all over the country.”

“He told me at the time he was a lawyer in Reykjavik.”

“He was probably working for the Harbour and Lighthouse Authority at that time,” Erlendur said.

“I’d just turned 20. Albert and I had two children when it happened. We started living together very young. He was at sea, Albert I mean. That didn’t happen very often. He ran a little shop and was an agent for an insurance company.”

“Does he know what happened?” Erlendur asked.

Katrin hesitated for a moment.

“No, I never told him. And I’d prefer it if you didn’t tell him now.”

They fell silent.

“Didn’t you tell anyone what happened?” Erlendur asked.

“I didn’t tell anyone.” She fell silent again.

Erlendur and Elinborg waited.

“I blame myself for it. My God,” she sighed. “I know that isn’t right of me. I know it was none of my doing. It was nearly 40 years ago and I’m still accusing myself although I know I shouldn’t. Forty years.”

They waited.

“I don’t know how much detail you want me to go into. What matters to you. As I said, Albert was at sea. I was out having fun with some friends and we met these men at the dance.”

“These men?” Erlendur interjected.

“Holberg and someone else who was with him. I never found out what his name was. He showed me a little camera that he carried around with him. I spoke to him about photography a bit. They went back to my girlfriend’s place with us and we went on drinking there. There was a group of four of us girlfriends who went out together. Two of us were married. After a while I said I wanted to go and he offered to walk me home.”