“We need to find his boot,” Sigurdur Oli said.

They all looked at the sock with the hole in it.

“This can’t be happening,” Elinborg sighed.

Detectives were searching for footprints in the garden but darkness was falling and they couldn’t see much on the frozen ground. The garden was covered with a coat of slippery ice, occasional clusters of grass poking through it. The district medical officer had confirmed the death and was standing where he thought he would be sheltered from the gale, trying to light a cigarette. He was uncertain about the time of death. Somewhere in the past hour, he thought. He had explained that the forensic pathologist would calculate the exact time of death by correlating the degrees of frost with the body temperature. On first impression the doctor could not identify a cause of death. Possibly a fall, he said, looking up at the gloomy block.

The body had not been disturbed. The pathologist was on his way. If possible he preferred to visit the crime scene and examine the surroundings with the police. Erlendur was concerned at the ever-growing crowd gathering at the corner of the block, who could see the body lit up by the flashing cameras. Cars cruised slowly past, their passengers absorbing the scene. A small floodlight was being erected to enable a closer examination of the site. Erlendur told a policeman to cordon off the area.

From the garden, none of the doors appeared to open out onto a balcony from which the boy might have fallen. The windows were all shut. This was a large block of flats by Icelandic standards, six storeys high with four stairwells. It was in a poor state of repair. The iron railings round the balconies were rusty. The paint was faded and in some places it had flaked off the concrete. Two sitting-room windows with a single large crack in each were visible from where Erlendur stood. No one had bothered to replace them.