There was no answer. He peered inside the flat and called his name again, but there was no response. They’d been living on the upper floor for several years but did not know the old man in the basement well. The elder son, 9 years old, was not as cautious as his father and quick as a flash he was in the neighbour’s sitting room. A moment later the child came back and said there was a dead man in the flat, and he really didn’t seem too perturbed by it.

“You watch too many movies,” the boy’s father said and cautiously made his way into the flat where he saw his neighbour lying dead on the sitting-room floor.

Erlendur knew the dead man’s name. It was on the doorbell. But to avoid the risk of making an idiot of himself he put on some thin rubber gloves and fished the man’s wallet out of a jacket hanging on a peg by the front doorway and found a payment card with a photograph on it. The man’s name was Holberg, 69 years old. Dead in his home. Presumed murdered.

Erlendur walked around the flat and pondered the simplest questions. That was his job: investigating the obvious. Forensics handled the mysterious. He could see no signs of a break-in, neither on the windows nor the doors. On first impression the man seemed to have let his assailant into the flat himself. The upstairs neighbours had left footprints all over the front hallway and sitting-room carpet when they came in out of the rain and the attacker must have done the same. Unless he took off his shoes by the front door. It looked to Erlendur as if he had been in too much of a rush to have had the chance to take off his shoes.

The forensic team had brought along a vacuum cleaner to collect the tiniest particles and granules from which to produce clues. They searched for fingerprints and mud that did not belong in the house. They looked for something extraneous. Something that had left destruction in its wake.

For all Erlendur could see, the man had shown his visitor no particular hospitality.