Columbine High School Shooting Timeline

Source(s):
https://en.wikipedia.org/wiki/Eric_Harris_and_Dylan_Klebold
https://en.wikipedia.org/wiki/Columbine_High_School_massacre
http://www.acolumbinesite.com

Key:
Green events mean nothing horribly bad (Them walking during the massacre or before and after the massacre)
Orange events mean something bad happening during the massacre but with no injury or death
Red events mean events with injury and/or death