At 11:10 a.m. on Tuesday, April 20, 1999, Dylan Klebold and Eric Harris arrived at Columbine High School. Each drove separately and parked in spots in the junior and senior parking lots, flanking the cafeteria. Around 11:14, the boys carried two 20-pound propane bombs (with timers set for 11:17) in duffel bags and placed them near tables in the cafeteria. No one noticed them place the bags; the bags blended in with the hundreds of school bags that the other students had brought with them to lunch. The boys then went back to their cars to wait for the explosion.
Nothing happened. (It is believed that if the bombs had exploded, it is probable that all 488 students in the cafeteria would have been killed.)
The boys waited a few extra minutes for the cafeteria bombs to explode, but still nothing happened. They realized that something must have gone wrong with the timers. Their original plan had failed, but the boys decided to go into the school anyway.
Klebold, wearing cargo pants and a black T-shirt with "Wrath" on the front, was armed with a 9-mm semi-automatic handgun and a 12-gauge double-barrel sawed-off shotgun. Harris, wearing dark-colored pants and a white T-shirt that said "Natural Selection," was armed with a 9-mm carbine rifle and a 12-gauge pump sawed-off shotgun. Both wore black trench coats to hide the weapons they were carrying and utility belts filled with ammunition. Klebold wore a black glove on his left hand; Harris wore a black glove on his right hand. They also carried knives and had a backpack and a duffel bag full of bombs.
At 11:19, the two pipe bombs that Klebold and Harris had set up in an open field several blocks away exploded; they timed the explosion so that it would be a distraction for police officers.
At the same time, Klebold and Harris started firing their first shots at students sitting outside the cafeteria. Almost immediately, 17-year old Rachel Scott was killed and Richard Castaldo was injured. Harris took off his trench coat and both boys kept firing.
Unfortunately, many of the other students didn't realize yet what was happening. It was only a few weeks until graduation for the seniors and as is tradition among many U.S. schools, seniors often pull a "senior prank" before they leave. Many of the students believed that the shootings were just a joke - part of a senior prank - so they didn't immediately flee the area.
Students Sean Graves, Lance Kirklin and Daniel Rohrbough were just leaving the cafeteria when they saw Klebold and Harris with guns. Unfortunately, they thought the guns were paint ball guns and part of the senior prank. So the three kept walking, heading toward Klebold and Harris. All three are wounded.
Klebold and Harris swiveled their guns to the right and then shot at five students who were eating lunch in the grass. At least two were hit - one was able to run to safety while the other was too debilitated to leave the area.
As Klebold and Harris walked, they nearly continually threw small bombs into the area.
Klebold then walked down the stairs, toward the injured Graves, Kirklin and Rohrbough. At close range, Klebold shot Rohrbough and then Kirklin. Rohrbough died instantly; Kirklin survived his wounds. Graves had managed to crawl back down to the cafeteria, but lost strength in the doorway. He pretended to be dead and Klebold walked over him to peer into the cafeteria.
The students in the cafeteria started looking out the windows once they heard gunfire and explosions, but they too thought it was either a senior prank or a film being made. A teacher, William "Dave" Sanders, and two custodians realized that this was not just a senior prank and that there was real danger. They tried to get all the students away from the windows and to get down on the floor. Many of the students evacuated the room by going up the stairs to the second level of the school. Thus, when Klebold peered into the cafeteria, it looked empty.
While Klebold was looking into the cafeteria, Harris continued shooting outside. He hit Anne Marie Hochhalter as she was getting up to flee.
When Harris and Klebold were back together, they turned to enter the school through the west doors, firing as they went. A policeman arrived on the scene and exchanged fire with Harris, but neither Harris nor the policeman was injured. At 11:25, Harris and Klebold entered the school.
Inside the School
Harris and Klebold walked down the north hallway, shooting and laughing as they went. Most of the students not at lunch were still in class and didn't know what was going on. Stephanie Munson, one of several students walking down the hall, saw Harris and Klebold and tried to run out of the building. She was hit in the ankle but managed to make it to safety. Klebold and Harris then turned around and headed back down the hallway (toward the entrance they had gone through to enter the school).