Wallander thought about the coming evening. Inese would be waiting for him in the hotel nightclub and pretending to be his mistress, to take him to his appointment with Baiba Liepa.

"Let's keep it low key," he said. "We're police officers after all, not actors celebrating a successful first night. Besides, I've already got something arranged for tonight. A young lady has agreed to keep me company."

Murniers smiled and produced a bottle of vodka from one of his desk drawers.

"That's something we wouldn't want to spoil," he said. "Let's drink a toast here and now!"

They're in a hurry, Wallander thought. They can't get me out of the country quickly enough.

They drank one another's health. Wallander raised his glass to the two colonels, and wondered if he would ever discover which one had signed the order leading to the murder of the major. That was the only thing he was still doubtful about, the only thing he couldn't know. Putnis or Murniers? What was quite certain now was that Major Liepa had been right. His secret investigations had led him to a truth he had taken with him to the grave, unless he had left a record. That is what Baiba Liepa would have to find if she wanted to know who had killed her husband, if it was Murniers or Putnis. Only then would she discover why Upitis had made a false confession in a desperate attempt to find out which of the colonels was responsible for the major's death.

Here I am drinking with one of the worst criminals I've ever come across, Wallander thought. The only thing is, I don't know which one it is.

"We shall accompany you to the airport in the morning, of course," Putnis said when the toasts were over.

Wallander left police headquarters feeling like a newly released prisoner, marching a few paces behind Sergeant Zids. They drove through the streets with the sergeant pointing out various places of interest. Wallander looked and nodded, muttering "yes" and "very pretty" when it seemed appropriate. But his thoughts were miles away. He was thinking about Upitis, and the choice he'd obviously been given. What had Murniers or Putnis whispered in his ear? What had they produced from their store of threats, the scope of which Wallander hardly dared imagine? Perhaps Upitis had a Baiba Liepa of his own, perhaps he had children. Did they still shoot children in Latvia? Or was it sufficient just to threaten that every door would be closed to them in future, that their future would be over before it had even started? Was that how a totalitarian state functioned? What choice did Upitis have? Had he saved his own life, his family, Baiba Liepa, by pretending to be the murderer? Wallander tried to recall the little he knew about the show trials that had led to a series of appalling injustices throughout the history of communism. Upitis fitted into that pattern somewhere or other. Wallander knew he would never be able to comprehend how people could be forced to admit to crimes they could never have committed, admit to murdering their best friend deliberately and in cold blood.

I'll never know, he thought. I'll never know what happened, and that's just as well because I'd never be able to understand it anyway. But Baiba Liepa would understand, and she has got to know. Someone is in possession of the major's last will and testimony, his investigation is not dead, it's still alive but it is outlawed and hiding somewhere where not only the major's soul is keeping watch over it.

What I'm looking for is the "Guardian", and that's something Baiba Liepa must know. She must know that somewhere, there is a secret that mustn't be lost. It's so cleverly hidden that nobody but her will be able to find it and interpret it. She was the person he trusted, she was the major's angel in a world where all the other angels had fallen.

Sergeant Zids stopped before a gate in the ancient city wall of Riga, and Wallander got out of the car, realising it must be the Swedish Gate that Mrs Putnis had spoken about. He shivered. It had grown cold again. He inspected the cracked brick wall absent-mindedly, and tried to decipher some ancient symbols carved into it. He gave up more or less straight away, and went back to the car.

"Shall we go on?" the sergeant asked.

"Yes," said Wallander. "I want to see all there is to see."

He had realised that Zids liked driving, and all alone in the back seat, despite the cold, despite the sergeant's constant glances in the rear-view mirror, he preferred the car to his hotel room. He was thinking about the evening, about how essential it was that nothing should prevent his meeting with Baiba Liepa. For a moment he considered contacting her at the university, and telling her what he knew in a deserted corridor. But he had no idea what subject she taught, and he didn't even know if there was more than one university in Riga.

There was also something else that had begun to form in his mind. The brief meetings he had had with Baiba Liepa, although fleeting and overshadowed by the grim point of departure, had been more than mere conversations about a sudden death. They had an emotional content far beyond what he was used to. Deep down he could hear his father's tetchy voice bewailing his son who had gone astray and not only become a police officer but had also been stupid enough to fall for the widow of a dead Latvian police officer.

Is that the way it was? Had he really fallen in love with Baiba Liepa?

As if Sergeant Zids could read his thoughts, he stuck out his arm and pointed to a long, ugly building, telling him that it was a part of Riga University. Wallander contemplated the grim brick edifice through the misted-up car window. Somewhere in there was Baiba Liepa. All official buildings in this country looked like prisons, and it seemed to Wallander their occupants were really prisoners. Not the major, and not Upitis, although he was now a real prisoner and not just one trapped in an endless nightmare.

He suddenly felt tired of driving round with the sergeant, and requested him to return to the hotel. Without knowing why, he asked him to come back at 2 p.m.

He spotted one of the men in grey immediately, and it occurred to him that the colonels no longer needed to pretend. He went into the dining room and deliberately sat down at a different table, ignoring the anxious face of the waiter who came to attend to him. I can really stir things up by refusing to co-operate with the government department that takes care of table placing, he thought, feeling furious. He slammed himself into the chair, ordered a beer and schnapps, and then noticed that the boil he got on his buttock from time to time had reappeared, making him even angrier. He stayed in the dining room for more than two hours, and whenever his glass was empty he beckoned the waiter and ordered a refill. As he grew more and more drunk, he staggered around in his mind and, in a burst of sentimentality, he imagined taking Baiba Liepa back to Sweden with him. As he left the dining room, he couldn't help waving to the man in grey who was keeping watch from one of the sofas. He took the lift to his room, lay down on the bed and fell asleep. Much later somebody started knocking on a door somewhere inside his head. It took him a while to realise that it was the sergeant knocking on his door. Wallander jumped out of bed, yelled at him to wait, and doused his face with cold water. He asked the sergeant to take him out of town to a forest where he could go for a walk and prepare for his meeting with the lover who would take him to Baiba Liepa.

It was cold in the forest, the ground was hard under his feet and it seemed to Wallander he was in an impossible situation. We live in an age when the mice are hunting the cats, he thought. But that isn't true either, as nobody knows any more who are the mice and who the cats. That sums up my situation precisely. How can I be a police officer when nothing is what it seems to be any more, nothing makes sense. Not even Sweden, the country I once thought I understood, is an exception. A year ago I drove a car in an advanced state of intoxication, but I wasn't punished because my colleagues rallied round to protect me – just another case of the criminal shaking hands with the man who's chasing him.