Colonel Putnis was on the terrace to welcome them. He had discarded his police uniform in favour of a well-cut suit that reminded Wallander of the clothes worn by the dead men in the life-raft. Standing by his side was his wife, a woman much younger than her husband. Wallander guessed she was not yet 30. When they were introduced it emerged that she spoke excellent English, and Wallander strode into the handsome mansion with that special kind of well-being one only gets on completing a long and strenuous journey. Colonel Putnis, crystal whisky glass in hand, showed him round the house, and the colonel made no attempt to conceal his pride. Wallander could see that the rooms were furnished with pieces imported from the West, giving the house a luxurious, yet restrained air.

No doubt I'd have been just like this couple if I lived in a country where everything seems nearly to be on the point of running out or breaking down, he thought. But the house must have cost a great deal of money, and he was surprised that a police colonel could earn as much. Bribes, he thought. Bribes and corruption. But then he quashed the thought immediately. He didn't know Colonel Putnis and his wife Ausma. Perhaps there were still such things as family fortunes in Latvia, despite the fact that those in government had had nearly 50 years in which to change all the financial norms? What did he know about it? Nothing.

They dined by the light of a tall candelabra. Wallander gathered from the conversation that Ausma also worked for the police, but in a different sector. He had the impression that her work was top secret, and it occurred to him that she might belong to the local section of the Latvian KGB. She asked him a lot of questions about Sweden, and the wine encouraged him to be expansive, despite his efforts to control himself.

After dinner Ausma disappeared into the kitchen to make coffee. Putnis served cognac in a living room where attractive leather armchairs stood in various groups. Wallander would never be able to afford furniture like that no matter how long he worked, and the thought made him aggressive. He felt a vague personal responsibility. It was as if – by not protesting – he would have contributed to the bribes that made Colonel Putnis's home affordable.

"Latvia is a land of enormous contrasts," he said, stumbling over the English words. "Isn't Sweden as well?"

"Of course – but not as obviously as here. It would be unthinkable for a Swedish police officer to live in a house like yours."

Colonel Putnis stretched out his hands as if to excuse himself.

"My wife and I are not rich," he said, "but we have lived frugally for many years. I'm 55 now, and would like to live in comfort in my old age. Is there anything wrong with that?"

"I'm not talking about rights and wrongs," Wallander said, "I'm talking about differences. When I met Major Liepa, it was the first time I'd come across anybody from one of the Baltic states. I had the impression he came from a country with much poverty."

"There are a lot of poor people here, I'm not denying that."

"I'd like to know how things really stand."

Colonel Putnis's gaze was penetrating. "I don't think I understand your question."

"With regard to bribes. Corruption. Links between criminal organisations and politicians. I'd like to know the answer to something Major Liepa said when he came round to my flat in Sweden. Something he said when he was about as drunk as I am now."

Colonel Putnis observed him with a smile. "Of course," he said. "Of course I shall explain if I can – but first I need to know what Major Liepa actually said."

Wallander repeated the invented quotation he'd presented to Colonel Murniers a few hours earlier.

"Irregularities do occur, even in the Latvian police force,"

Putnis said. "Many police officers receive low wages, and the temptation to accept bribes can be great. At the same time, though, I have to say that Major Liepa had a tendency to exaggerate the prevailing circumstances. His honesty and industry were admirable, of course, but occasionally he may have been guilty of confusing facts with emotional misconceptions."

"You mean he was exaggerating?"

"Unfortunately I think he was."

"Even when he claimed that a high-ranking police officer was deeply embroiled in criminal activity?"

Colonel Putnis warmed his cognac glass in his hands. "He must have been referring to either Colonel Murniers or myself," he said. "That surprises me. His accusation was both inaccurate and irrational."

"But there must have been some explanation?"

"Perhaps Major Liepa thought Murniers and I were getting old too slowly," Putnis said with a smile. "Perhaps he was dissatisfied by the fact that we stood between him and his own promotion?"

"Major Liepa didn't give me the impression of being especially concerned with his own career."

Putnis nodded sagely. "Let me suggest a plausible explanation," he said, "but I must stress it is strictly between ourselves."

"I do not normally betray confidences."

"About ten years ago Colonel Murniers succumbed to an unfortunate weakness," Putnis said. "He was caught taking a bribe from a director of one of our textile factories who had been arrested on suspicion of embezzlement. The money taken by Murniers was seen as compensation for his turning a blind eye to the fact that some of the arrested man's fellow-criminals had been given the opportunity to conceal certain documents that could have provided crucial proof." "What happened next?"

"The matter was hushed up. The businessman was given a symbolic sentence, and within a year he was appointed head of one of the country's biggest sawmills."

"What happened to Murniers?"

"Nothing. He was full of remorse. He had been overworked at the time, and had gone through a painful and lengthy divorce. The tribunal assigned the task of judging the case decided that the offence should be forgiven. Perhaps Major Liepa had assumed, wrongly, that a temporary weakness was in fact a chronic character defect? That's the only explanation I can give you. Can I pour you some more cognac?"

Wallander held out his glass. Something Colonel Putnis had said, and also Murniers earlier, nagged at him, although he couldn't put his finger on it. Just then Ausma came in with the coffee tray, and began to tell Wallander with great enthusiasm about all the sights he must see before leaving Riga. As he listened to her, his anxiety nagged away in the back of his mind. Something crucial had been said, something barely noticeable: but it had caught his attention even so.

"The Swedish Gate," Ausma said. "You haven't even seen our monument from the time when Sweden was one of the great powers of Europe?"

"I must have missed it."

"Sweden is still a great power even today," Colonel Putnis said. "A small country, but much envied on account of its great riches."

Afraid of losing the thread of the vague suspicion he had intuitively registered, Wallander excused himself and went to the lavatory. He locked the door and sat down.

Many years ago, Rydberg had taught him the importance of immediately following up on a clue that seemed to dangle so close to his eyes that it was difficult to see. It dawned on him. Something Murniers had said, that had been contradicted by Colonel Putnis only moments ago, using almost the same words.

Murniers had spoken of Major Liepa's rationality, and Colonel Putnis about his irrationality. In view of what Putnis had vouchsafed about Murniers, perhaps that wasn't difficult to understand; but as Wallander sat there on the lavatory lid, he realised that he would have expected the pair to have precisely the opposite views.

"We suspect Murniers," Baiba Liepa had said. "We suspect he was betrayed."

Maybe I've got it all wrong, Wallander thought. Maybe I'm seeing in Murniers what I ought to be looking for in Colonel Putnis? The one who spoke of Major Liepa as rational was the one I'd have expected to think the opposite. He tried to recall Murniers's voice, and it came to him that the colonel had possibly implied something more. Major Liepa is a rational person, a rational police officer: that would suggest his suspicions are correct.