turned off the shower. The water wasn’t running when he was found. Tragically, turning off the water will have only made the situation worse. The fan in the shower would have speeded up the process of spreading the now lethal gas around the room. It wouldn’t take much of the substance to kill him. And the beauty of the scheme is that the killing agent evaporates in the air. The evidence literally disappears. And the method of activation is flushed down the drain by the shower. We just struck lucky with our trace of jelly.’ Moberg could hear the admiration in her voice. He never understood the forensic technicians. He found them a strange bunch with a warped sense of humour. Probably due to too many hours poking around dead bodies, sniffing out weird substances and obsessing over blood stains. But they had their uses. ‘That’s the last time I’m going to let my wife make me jelly. But what about the crystals? We need to know where to look.’ ‘Sorry. I can’t be much help there. The effects on Ekman’s system are similar to the ones suffered by the Jews in the gas chambers. The Germans tended to use Zyklon B. It was originally manufactured as an insecticide for delousing clothes. Then they discovered it worked on people. Apparently it took ten grams to kill an insect, but only nought-point-three grams to kill a human being.’ ‘Could it be Zyklon B?’ ‘I doubt it after all these years. The Second World War was a long time ago. Could be a modern equivalent. Your best bet is to have a look at pharmaceutical companies. That’s all I can think of.’ ‘That doesn’t make me feel any better.’ Westermark and Wallen were ploughing their way through the members of the Ekman & Johansson staff and checking everyone’s movements for the entire day before Tommy Ekman’s death. They took separate rooms so that they could get through them as quickly as possible. Wallen noticed that Westermark had taken most of the women, with one obvious exception. Elin Marklund. Moberg had given them strict instructions that Wallen was to talk to her. It was time that they confirmed their suspicions that Marklund was the woman that Ekman had made love to before his death. If it wasn’t her, the team would have to look somewhere else. It would also help fill in his movements that night. If they had made love in the office then he was unlikely to have gone anywhere else afterwards. He would have gone straight home to his apartment and then called his wife. Despite Westermark’s objections, Moberg insisted that Klara Wallen tackle Marklund. He reasoned that Marklund was more likely to confess to a woman than an abrasive male officer. He knew what Westermark was like and he didn’t want to run the risk of Marklund clamming up because Westermark was pushing her too hard. Wallen greeted Marklund with a smile. She always admired confident women and she put Marklund in that category. She envied their self-assurance. Her own rise through the ranks had been steady rather than spectacular. She was the first to admit that it should have been quicker because, unlike other female colleagues like Anita Sundström, she hadn’t been encumbered by bringing up a family. She had had a husband. Now she had a partner. But no kids. It wasn’t a biological disappointment. She just didn’t want any. Now, at the age of forty, nephews and nieces filled the void that might have been there. Children were fine as long as you didn’t have to live with them. As Marklund took her seat opposite the desk in Ekman’s office, where Wallen was holding her interviews, she wondered if this elegant woman was a mother. ‘We’re talking to everyone in order to establish their movements on the day before Tommy Ekman died.’ ‘Why?’ Marklund asked. Wallen was taken off-guard for a moment, as Marklund was the first person to challenge the statement. ‘We need to know how each member of staff spent their day. Who could have had access to this office?