Columbine

I am reading the novel Columbine by Dave Cullen. It is a comprehensive examination of the Columbine High School massacre. The book is written in a very unique way, the chapters alternate between two different storeis involving the people of this tragedy. As far as I've read I can decifer that the two stories alternate between the 'before' story of the killers' evolution toward murder, and the 'after' story of the survivors. The before story focuses mainly on the killers high school years, trials and tribulations. As I am reading it is giving me more of an idea about exactly who the killers really were and what was going through their mind before and after the attacks.