The following diagrams show the significant events and movements of Eric Harris and Dylan Klebold on April 20, 1999. The witnesses to each event are shown as green dots. The injured are shown as yellow only during the event that caused the injury and return to green if they witnessed other events. The deceased are shown as red and convert to gray once that event has passed. Harris is shown as a red dot with the letter “H” inside it and Klebold is shown as a blue dot with the letter “K” inside it.

The diagrams only show the portions of the school where the events are occurring. Where appropriate an overview of the school is shown with a red square indicating what area of the school is magnified.