Columbine

Eric Harris was a textbook psychopath, and Dylan Klebold was an angry depressive. I found it weird that Eric Harris already had a criminal record a year before the Columbine attacks actually happened. The reason behind that being that Eric was creating CO2 bombs in his backyard and setting them off.
  On August 7, 1997 a "concerned citizen" read Eric's web site and called the sheriffs office. On that day about a year before Columbine the killers' names permanently entered the law enforcement system.
I feel as if something should have done to keep an eye on this boy, either his parents kept a closer look or the law enforcement should have because clearly he was a dangerous subject before the attacks.