Lisbeth Salander is convinced that there is a connection between Zalachenko and Bjurman and therefore sets out to find evidence for such a connection because she has no such evidence as yet in which case why is she so convinced that there is a connection? This is a contradiction. We, the readers, do not initially notice the contradiction because we already know that there is a connection between Zala and Bjurman and we expect Salander to be on the trail but she has to have something to start with. Knowing that Zala is involved with prostitution, knowing that prostitution involves bikers and learning that Bjurman has met someone who then met a biker, she might start to hypothesize a connection between Zala and Bjurman but at that stage it would only be a hypothesis. In terms of the plot, she has to mention a (possible) Zala-Bjurman connection to Dag in order to set in motion the murders of Bjurman, Dag and Mia.
