“She has a brother in Iceland,” the interpreter said. “I’ll contact him.”

“Do you know this woman?” Elinborg asked.

The interpreter nodded.

“Have you lived in Thailand?”

“Yes, for several years,” the interpreter said. “I first went there as an exchange student.”

She said her name was Gudny, and she was slender and quite short, with dark hair and large glasses. She wore a thick woollen sweater and jeans under a black coat, and had a white woollen shawl over her shoulders.

When they arrived back at the flats, the woman asked to be shown where her son was found and they took her into the garden. It was pitch dark by now but the forensics team had set up lights and cordoned off the area. News of the murder had spread rapidly. Elinborg noticed two bouquets of flowers laid against the wall of the block of flats, where a growing crowd was gathering by the police cars, looking on in silence.

The mother went through the police cordon. Forensics technicians in white overalls stopped their work and watched her. She was soon standing alone but for the interpreter at the place where her son had been found dead. She knelt down, placed the palm of her hand on the ground and wept.

Erlendur emerged from the darkness and watched her.

“We ought to go up to her flat,” he said to Elinborg, who nodded in reply.

They stood in the cold for some time, waiting for the two women to come back. Eventually, the detectives followed them out of the garden and into the stairwell in the part of the block where the mother lived. Elinborg introduced Erlendur to her as a detective who would be taking part in the investigation into her son’s death.

“Perhaps you’d prefer to talk to us later,” Erlendur said. “But the fact is that the sooner we receive information, the better, and the more time that passes after the deed, the more difficult it might be to find the person who did it.”

Erlendur stopped talking to allow the interpreter to translate what he had said. He was about to continue when the mother looked at him and said something in Thai.

“Who did it?” the interpreter said at once.

“We don’t know,” Erlendur said. “We’ll find out”

The mother turned to the interpreter and spoke again, a look of acute anxiety on her face.

“She has another son and she’s worried about him,” the interpreter said.

“Does she have any idea where he might be?” Erlendur asked.

“No,” the interpreter said. “He should have left school around the same time as his brother.”

“Is he older?”

“Five years older,” the interpreter said.

“So that makes him … ?”

“Fifteen.”

The mother hurried up the stairs in front of them until they reached the fourth floor, the second-highest. Erlendur was surprised that there was no lift in such a tall building.

Sunee unlocked the flat, shouting something before the door was even open. Erlendur thought it was the name of her other son. She ran around the flat but, seeing that no one was home, stood helpless and strangely alone in front of them until the interpreter put an arm around her, led her into the sitting room and sat down on the sofa with her. Erlendur and Elinborg followed, and they were joined by a thin man who had come running up the stairs and introduced himself as the vicar of the local church and an experienced trauma counsellor.

“We have to find his brother,” Elinborg said. “Let’s hope nothing’s happened to him.”

“Let’s hope it wasn’t him who did this,” Erlendur said.

Elinborg looked at him in astonishment.

“The things you think of!”

She looked around her. Sunee lived in a small two-bedroom flat. The front door opened straight onto the sitting room, while to one side was a small corridor leading to a bathroom and two bedrooms. The kitchen was beside the sitting room. A strong aroma of oriental spices and exotic cuisine filled the flat, which was spotlessly tidy and decorated with ornaments from Thailand. All over the walls and tables were photographs that Elinborg imagined showed the mother’s relatives on the other side of the globe.

Erlendur was standing beneath a red paper parasol with a picture of a yellow dragon on it, which served as a lampshade. When the interpreter said she was going to make tea, Elinborg followed her into the kitchen. Sunee remained on the sofa and the vicar sat down beside her. Erlendur said nothing and waited for the interpreter to come back.

Gudny knew a little about Sunee’s background and recounted it to Elinborg in the kitchen in half-whispers. She was from a village about two hundred kilometres from Bangkok and had been brought up in a household where three generations lived together in straitened circumstances. There were many children and Sunee had moved to the capital with two of her brothers when she was fifteen. She did manual labour, mainly in laundries, and lived in poor, cramped conditions with her brothers until she was twenty. After that she had described herself as being alone, working in a large textile factory manufacturing cheap clothing for western markets. Only women worked there and the wages were low. Around that time she met a man from a far-away country, an Icelander, at a popular nightclub in Bangkok. He was several years older than her. She had never heard of Iceland.

While the interpreter told Elinborg this story and the vicar consoled Sunee, Erlendur walked around the sitting room. There was an oriental charm about the flat. A small altar stood halfway along the wall with cut flowers, incense and a bowl of water, and a beautiful picture from rural Thailand. He perused the cheap ornaments, souvenirs and framed photographs, some of them showing two boys at different ages. Erlendur presumed these were the deceased and his brother. He picked up from the table what he took to be a photograph of the elder boy and asked Sunee whether it was him. She nodded. He asked to borrow it and took it to the front door, where he gave it to the policeman who was standing there and told him to distribute it at the police station and to start looking for the lad.

Erlendur was holding his mobile in his hand when it began to ring. It was Sigurdur Oli.

He had traced the boy’s tracks from the garden, to a narrow path and down it across a quiet road, past houses and gardens until it stopped beneath the wall of a small electricity utility building or substation that was covered in graffiti. The substation was about five hundred metres from the boy’s home and not far from the local school. On first impression, Sigurdur Oli could see no signs of a struggle. More policemen descended on the scene and began searching with flashlights for the murder weapon in nearby gardens and on paths, streets and in the school yard.

“Keep me informed,” Erlendur said. “Is it far from this place to the school, did you say?”

“It’s really next door. But that doesn’t mean the boy was stabbed here, even if this is where the tracks stop.”

“I know,” Erlendur said. “Talk to people at the school, the principal, the staff. We need to interview the boy’s teachers and classmates. His friends in the neighbourhood too. Everyone who knew him or can tell us anything about him.”

“That’s my old school,” Sigurdur Oli mumbled.

“Really?” Erlendur said. Sigurdur Oli rarely talked about himself. “Are you from this part of town?”

“I’ve hardly been to the place since,” Sigurdur Oli said. “We lived here for two years. Then we moved again.”

“And?”

And nothing.”

“Do you think they’ll remember you, your old teachers?”

“I hope not,” Sigurdur Oli said. “What class was the boy in?”

Erlendur went into the kitchen.

“We need to know what class the boy was in,” he said to the interpreter.

Gudny went into the sitting room, spoke with Sunee and came back with the information.

“Have there been any racial clashes in this area?” Erlendur asked her.