And the victims, investigators later learned, were chosen randomly from library researchers. They felt that the Unabomber had been raised in Chicago. They believed later that he lived in Salt Lake City and in the San Francisco area. This turned out to be true. His occupation proved to be more elusive, with theories ranging from aircraft mechanic to scientist. Even the gender wasn't certain. Although investigators believed the bomber was most likely to be male, they also investigated several female suspects. The big break came in 1995