Wallander could feel relief seeping through his body. It was all over.

Putnis smiled.

"All that remains is for me to read Major Liepa's documents," he said. "And now you can go back home for real, Inspector Wallander. We are deeply grateful for the help you have given us."

Wallander took the numbered tag out of his pocket.

"The file is blue," he said. "It's in a carrier bag at the left luggage desk. Along with two records that I would like to have back."

Putnis laughed. "You really are very clever, Mr Wallander. You don't put a foot wrong unless you're forced to."

Was it something in Putnis's tone of voice that gave him away? Wallander never managed to work out precisely why he was suddenly struck by the awful thought – but just as Putnis was putting the tag into his pocket, it became crystal clear to Wallander that he had just made the biggest mistake of his life. He simply knew without knowing why he knew. He could no longer distinguish between intuition and rational thought, and his mouth was as dry as a desert.

Putnis continued to smile as he took his pistol from out of his pocket. His men closed in, spreading themselves all over the roof and pointing their machine guns at Baiba and Wallander. She didn't seem to grasp what was happening, and Wallander was struck dumb with fear and humiliation. At that very moment the fire door opened, and Sergeant Zids stepped out on to the roof. It occurred to Wallander's confused mind that Zids must have been there behind the door all the time, waiting to make his entrance. The show was over now, and he didn't need to wait in the wings any more.

"Your only mistake," Putnis said, his voice expressionless. "Everything I've just told you is absolutely true, of course. The only thing that distances my words from reality is my good self. Everything I said about Murniers applies to me. You were right and wrong at the same time, Inspector Wallander. If you had been a Marxist, like me, you would have realised that one must occasionally stand the world on its head in order to put it on its feet."

Putnis took a step backwards. "I trust you will realise that it is not possible for you to return to Sweden," he said. "After all, you'll be quite close to heaven when you die, up here on the roof."

"Not Baiba," Wallander pleaded. "Not Baiba."

"I'm so sorry," Putnis said.

He raised his gun, and Wallander realised he was going to shoot Baiba first. There was nothing he could do, he would die here on the roof in the centre of Riga. At that very moment the fire door burst open. Putnis gave a start and turned to see what had caused the unexpected noise. At the head of a large number of armed police officers pouring out on to the roof was Colonel Murniers. When he saw Colonel Putnis standing there with his gun in his hand, he did not hesitate. His own pistol was already drawn, and he shot Putnis through the chest, three bullets in rapid succession. Wallander threw himself over Baiba in order to shield her. A violent gun battle raged all over the roof. Murniers's and Putnis's men tried to hide behind chimneys and ventilators. Wallander saw he was in the firing line, and tried to pull Baiba with him behind Putnis's corpse. He suddenly noticed Sergeant Zids crouching behind one of the chimneys. Their eyes met, then Zids noticed Baiba, and it was immediately clear to Wallander that Zids was going to try to take both of them hostage in order to secure a safe passage for himself. Murniers's men outnumbered the others, and several of Putnis's henchmen had already been killed. Wallander could see Putnis's pistol lying beside his body, but before he could reach it Zids had flung himself at him. Wallander thrust his injured hand into Zids's face, and cried out in agony. Zids reeled from the force of the blow, his mouth started bleeding, but he had not been seriously hurt by Wallander's desperate reaction. There was hatred in his eyes as he raised his gun to shoot the Swedish police officer who had caused him and his superior so much trouble. But when the shot rang out and Wallander realised he was still alive, he opened his eyes and registered that Baiba was kneeling beside him. She had Putnis's pistol in her hands, and had shot Sergeant Zids between the eyes. She was crying, but he knew it was due to a mixture of fury and relief rather than the fear and misery she had been subjected to for so long.

The gunfire on the roof ceased just as suddenly as it had begun. Two of Putnis's men were wounded, the rest were dead. Murniers looked grim as he examined one of his own men who had received a number of gunshots to the chest, then he walked over to Baiba and Wallander.

"I'm sorry it had to turn out like this," he said apologetically, "but I had to know what Putnis said."

"You'll no doubt be able to read the full story in the major's papers," Wallander said.

"How could I have been sure they existed? And still less that you had found them?"

"By asking," Wallander said.

Murniers shook his head. "If I'd contacted either of you, I'd have entered into open warfare with Putnis, he'd have fled the country and we'd never have been able to catch him. I had no option but to keep watch over you by constantly following on the heels of Putnis's shadows."

Wallander suddenly felt far too weary to listen any more. His hand was throbbing and the pain was agonising. He took Baiba's hand and pulled himself up.

Then he passed out. When he came round he was on a treatment table in hospital, his hand was in plaster and the pain had gone at last. Colonel Murniers was standing in the doorway, cigarette in hand, watching him and smiling.

"Do you feel better now?" he asked. "Our doctors are very good. Your hand was not a pretty sight. You can have the x-rays to take home with you."

"What happened?" Wallander asked.

"You fainted. I'm sure I would have done as well, if I'd been in your situation."

Wallander looked round the examination room. "Where's Baiba?"

"She's at home in her flat. She was very calm when I left her there a few hours ago."

Wallander's mouth was dry. He sat up gingerly on the edge of the treatment table.

"Coffee," he said. "Can you get a cup of coffee here?"

Murniers burst out laughing.

"I've never known a man drink as much coffee as you do," he said. "Of course you can have some coffee. If you are feeling up to it, I suggest you come to my office so that we can wind up the whole business. Then I expect you and Baiba Liepa will have plenty to talk about. A police surgeon will give you an injection of painkillers if your hand starts hurting again. The doctor who put it in plaster said that could well happen."

They drove across the city. It was already quite late in the day, and it was starting to get dark. When they drove through the arch into the courtyard of the police headquarters, it seemed to Wallander that this must surely be for the last time. On the way up to his office, Murniers paused to unlock a safe and take out the blue file. An armed guard was sitting beside the imposing safe.

"I suppose it's a good idea to keep it locked up," Wallander said.

Murniers looked at him in surprise. "A good idea?" he echoed. "It's necessary, Inspector Wallander. Even if Putnis is now out of the way, it doesn't mean that all our problems are solved. We are still living in the same world as before. We are living in a country torn apart by conflicting forces, and we shan't get rid of those simply by putting three bullets into the chest of a police colonel."

Wallander reflected on Murniers's words as they continued to his office. A man with a coffee tray was standing to attention outside the door. Wallander recalled his first visit to that dingy room. It seemed like a distant memory. Would he ever be able to grasp everything that had happened in between?

Murniers took a bottle out of a desk drawer and filled two glasses.