"I've never touched another man, as a matter of fact... except for my father. It was my duty." (Larsson 496)
The seemingly normal CEO of the Vanger Corporation, Martin Vanger, was discovered to be anything but once Mikael realizes he was at Hedestad the day of Harriet's disappearance all those years ago. Blomkvist learned first hand what Martin was really like upon being caught investigating his house and finding the rifle that Blomkvist's formerly mysterious assailant had tried to kill him with. After being brought to Martin's personal torture chamber, the man himself admits that he kidnaps, rapes, and murders women in a bragging sense. He had been trained and conditioned by his father, Gottfried, to hate women and kill them. Martin also made subtle comments that point towards sexual abuse from his father and that he had developed a sort of Stockholm Syndrome as he was always willing to please his father. Even after his father's death he continues to kill women even bragging to Mikael that he had a woman in the chamber during his stay in Hedestad. It is more than obvious that Martin Vanger was a very deeply psychological disturbed individual. However, he was not responsible for Harriet's murder as he became violent and demanded to know what had happened to her when Mikael asked him if he killed her. Martin admitted he wanted to kill her, but the accident at Hedestad prevented him for doing so himself.