A bomb factory has also been discovered.
On 20 April 1999, two teenagers entered Columbine High School in Colorado with guns and explosives. They killed 12 students and a teacher, before turning their weapons on themselves. The event changed American classrooms forever, with school security becoming a multi-billion dollar industry. Now that many Columbine shooting survivors are parents themselves, they are facing the repercussions of the tragedy everyday.
An 11-hour siege in Sydney has ended after police raided a building where a man claiming to have a bomb strapped to his body