present case this was no longer mathematics but a vision of horror. They drove under Liljeholm Bridge, along Hornstull Strand, passed under the railroad bridge and turned up into the residential area where the old sugar mill had once been. Some children were playing in the gardens around the apartment houses, but not many. They parked the car and took the elevator to the seventh floor. Rang the doorbell, but no one came to the door. After waiting a while Martin Beck rang the bell of the apartment next door. A woman opened the door a chink. Behind her he caught a glimpse of a little girl of five or six. 'The police," Kollberg said reassuringly, showing his identity disk. 'Oh," the woman said. 'Do you know if the Oskarsson family are at home?" Martin Beck asked. 'No, they went away this morning. To relations somewhere. That's to say the wife and children." 'Oh, I'm sorry to have…" 'But it's not everyone who can," the woman cut in. "I mean go away." 'Do you know where they went?" Kollberg asked. 'No. But they'll be back on Friday morning. Then I think they're leaving again right away." She looked at them and said in explanation: 'Their vacation starts then." 'But the husband is at home?" 'Yes, this evening. You can call him up." 'Yes," Martin Beck said. The little girl grew fretful and tugged at her mother's skirts. 'The children get so peevish," she said. "You can't let them out. Or is it all right?" 'Preferably not." 'But some people have to," the woman said. "And a lot of children won't obey." 'Yes, unfortunately." Without a word they went down in the automatic elevator. Without a word they drove northwards through the city, aware of their powerlessness and of their ambivalent attitude to the society they were there to protect. They swung up into Vanadis Park and were stopped by a uniformed police officer who recognized neither them nor the car. There was nothing to see in the park. Except a few children who were playing, in spite of everything. And the indefatigable snoopers. When they got back to the intersection of Odengatan and Sveavägen Kollberg said: 'I'm thirsty." Martin Beck nodded. They parked, went into the Metro-pole restaurant and ordered fruit juice. Two other men were sitting at the bar. They had taken off then- coats and put them on the bar stools, an act of unconventionalism that showed how hot it really was. They were drinking whisky and soda, and talking earnestly between sips. 'It's because there's no proper punishment," the younger man said. "A lynching is what's needed." 'Yes," the older man agreed. 'I'm sorry to have to say it, but it's the only thing." Kollberg opened his mouth to say something but changed his mind and drained his glass of fruit juice in one gulp. Martin Beck was to hear much the same thing once more that day. In a tobacconist's, when he went in to buy a pack of cigarettes. The man in front of him was saying: '… and do you know what they ought to do when they catch this bastard. They ought to execute him in public, they should show it on TV, and they shouldn't do it all at once. No, bit by bit for several days." When the man had gone Martin Beck said: 'Who was that?" 'His name's Skog," the tobacconist said. "He has the radio workshop next door. Decent chap." Back at headquarters Martin Beck reflected that it wasn't so long since they used to chop a thief's hands off. Yet people still went on stealing. Plenty of them. In the evening he called up Bo Oskarsson's father. 'Ingrid and the children? I've sent them down to her mother and father in Öland. No, there's no phone there." 'And when will they be back?" 'On Friday morning. The very same evening we're going abroad. We don't damn well dare to stay here." 'No," Martin Beck said wearily. This was what happened on Tuesday the thirteenth of June. On Wednesday nothing at all happened. The weather grew hotter.
13 SOON AFTER eleven o'clock on Thursday something did happen. Martin Beck was