A Timeline of the April 20, 1999 Columbine High School Shooting

April 20, 1999, was a typically sunny, warm spring day at Columbine High School in Littleton, Colorado. But that day was anything but typical for the 1,950 students who were at school.

At around 11:20 a.m., school seniors Eric Harris, 18, and Dylan Klebold, 17, exited their cars in the school parking lot with their guns and started shooting, killing their first victim, Rachel Scott, 17, as she was eating lunch outside on the grass. The pair then went into Columbine High and continued their rampage. At the end of the day, 12 students were dead, along with one beloved teacher. A further 23 were wounded. At the time, it was the worst school shooting in U.S. history.

What follows is a timeline of the events of that horrific day.

Timeline of Events of the Columbine Shooting: April 20, 1999, 11:10 a.m. to 4:45 p.m.

11:10 a.m.

  • Eric Harris arrives at the student parking lot at Columbine High School and parks his 1986 gray Honda Civic in the south junior parking lot.
  • Dylan Klebold arrives shortly thereafter, and parks his 1982 black BMW in the southwest senior parking lot.
  • Harris speaks to one student and tells him to leave the school because he likes him.

Eric Harris & Dylan Klebold; Photo: www.youtube.com/watch?v=AUSJ6rqEWUY

11:14 a.m.

  • Harris and Klebold get out of their cars and walk into the school cafeteria carrying two large duffel bags containing 20-pound propane bombs set to detonate at 11:17 a.m. Harris determines that the cafeteria will be busiest at this moment, resulting in maximum casualties. They place the bags on the floor beside two lunch tables and walk outside.

11:17 a.m.

  • The two return to the school parking lot and sit in their respective cars waiting for the bomb to explode.
  • After the explosion, Harris and Klebold plan to shoot and kill any students fleeing the school.
  • The two gunman have timed bombs in their cars set to go off once they go back into the school.

 11:19 a.m.

  • Jefferson County Dispatch receives a 911 call reporting an explosion in a field. It is actually a diversionary device planted by Harris and Klebold. The bombs were supposed to divert the attention of police away from what is planned at Columbine. 

11:19 a.m. to 11:23 a.m.

  • Harris and Klebold stand together at the top of the steps at the west exterior entrance to Columbine High; both are wearing black trench coats and carrying a backpack and duffel bag.
  • At around 11:19 a.m., one of the two gunman yells, “Go! Go!” Harris and Klebold take sawed off shotguns from their bags. They begin shooting at students.
  • Rachel Scott, 17, is the first to die; she was eating lunch on the grass with her friend Richard Castaldo, who was seriously injured.
  • Three students —Daniel Rohrbough, Sean Graves, and Lance Kirklin—leave the school for a smoke break; they are hit by gunfire.
  • Klebold goes down the stairs to an area outside the cafeteria where the three students lay. He shoots Daniel Rohrbough, 15, at close range, killing him instantly. He also shoots Kirklin, but he survives.
  • Witnesses hear one of the gunmen shout, “This is what we always wanted to do. This is awesome!”

11:22 a.m.

  • The school custodian hits the record button on the VCR that records images of the cafeteria. It shows students becoming aware of what is happening outside; the curious look out the window, thinking it might be a senior prank.

11:23 a.m.

  • Jefferson County receives a 911 call from Columbine High School reporting a girl injured in the south parking lot.
  • Two police deputies are advised of a female down in the south parking lot at Columbine High.

11:24 a.m.

  • Teacher Dave Sanders and several of the school’s custodial staff realize what is going on and direct students to get down. They hide under the cafeteria tables.
  • Jefferson County Sheriff’s Deputy Neil Gardner, community resource officer at Columbine High School, gets out of his patrol car. Harris turns his attention to Gardner; he fires off 10 shots before his gun jams.
  • Gardner returns fire, shooting four times in Harris’ direction.
  • Harris is not hit and enters the school through the west doors.
  • Students in the cafeteria realize they are not witnessing a senior prank. Students are seen on the school’s surveillance video escaping up the stairs to the second level. Sanders is there directing them to safety, telling them to escape out the east-side exit doors.

Photo: www.youtube.com/watch?v=kIXjOLKhVkw

11:25 a.m.

  • Jefferson County Sheriff’s Office dispatch advises of possible shots fired at Columbine High School.
  • Teacher Patti Nielson, who is hiding under the front counter in the school library, calls 911 to report shots fired.

11:26 a.m.

  • After exchanging fire with Harris, Gardner calls for backup.
  • Harris leans out of a broken window on the set of double doors into the school and starts shooting a rifle.
  • Paul Smoker, a motorcycle patrolman, fires three rounds at Harris, who disappears into the school. Gunfire is heard from inside the building as more students run from the school.
  • Klebold and Harris are seen armed, standing inside the school’s northwest doors. Klebold fires a semi-automatic weapon toward students in the main hallway and down the library hallway.
  • Both are seen firing their weapons, laughing.
  • Klebold is last seen running down the north hall in the direction of the library hallway.
  • Dave Sanders, who is still on the second level, turns into the library hallway. He sees a gunman coming toward him and turns to head back the way he just came. Before turning the corner, he is shot in the head, neck, and torso.
  • Sanders crawls down the hallway where fellow teacher Richard Long helps him into a science lab classroom. A group of students gather around Sanders and administer first aid.

11:27 a.m.

  • Possible hand grenades are heard going off in the school.
  • Harris and Klebold walk up and down the library hallway randomly shooting their weapons and tossing pipe bombs, but they don’t hurt anyone.
  • A pipe bomb is thrown into a stairwell from the library hallway and lands in the cafeteria below. A massive flash is recorded on the cafeteria videotape.
  • Teacher Patti Nielsen, who instructed students to hide under the tables, reports that a gunman is just outside the library entrance.

Photo: www.youtube.com/watch?v=uhEwrh752Og

11:28 a.m.

  • Escaping students tell police the gunmen have Uzis or shotguns and are throwing hand grenades. They think the younger of the two gunmen is probably high school aged, wearing a black trench coat and backwards baseball cap. The second gunman is described as taller and a little older. He, too, is wearing a black trench coat.

11:29 a.m.

  • Jefferson County Dispatch alerts all units that Deputy Gardner is under fire, and the two suspects just ran into the building with large weapons.
  • Harris and Klebold walk into the school library. A 911 call records one of the males yelling, “Get up!”

11:29 a.m. to 11:36 a.m.

  • The gunmen walk through the library toward the west windows, killing one student. They blow out the windows toward police and fleeing students. Police return fire.
  • Harris and Klebold turn back toward those in the library and open fire. They kill four and injure four more.
  • They walk toward the library entrance and shoot out the display case near the front door, then fire at students in this section of the library: three are killed, four injured.
  • The killers reload their weapons and kill two more students; two more are also injured.
  • They then leave the library.
  • In just seven minutes, Harris and Klebold kill 10 and wound 12. Of the 56 people in the library, 24 escape injury.

11:36 to 11:44 a.m.

  • Klebold and Harris leave the library and walk down the hallway to the science area. The two are seen looking through windows of some of the classrooms, making eye contact with students. But they do not try to break into the locked rooms or harm any more students.
  • The two are heard shooting into empty rooms and throwing pipe bombs.
  • Their actions seem directionless at this point.
  • Harris and Klebold leave the science area and head down to the cafeteria. The cafeteria tape shows Harris kneeling down and resting his rifle on the stair, railing and firing several shots into one of the large duffel bags that contains a 20-pound propane bomb. It is thought he is trying to make it explode. It doesn’t.
  • The two shooters take drinks from water bottles left by fleeing students.
  • One student hiding in the cafeteria hears one of the shooters say, “Today the world’s going to come to an end.  Today’s the day we die.”

11:45 a.m.

  • Video shows Klebold throw something in the vicinity of the propane bomb.

11:46 a.m.

  • Klebold and Harris stay in the cafeteria for around two-and-a-half minutes.
  • As the gunmen walk away, videotape catches a partial detonation of a bomb and fire. The explosion could have been ignited by the device thrown by Klebold. The explosion causes a fire that activates five fire sprinklers in the area. Despite the fire and heat, neither of the 20-pound propane tanks explodes.

11:47 a.m.

  • One student is captured on the cafeteria videotape crawling out of the cafeteria side door.

11:49 a.m.

  • Harris and Klebold walk over to the office area.

11:53 a.m. to 11:55 a.m.

  • A 911 call from a school secretary and security officer hiding in the school’s main office reports hearing shots fired in the office, into the ceiling, and in the art hallway.
  • Police confirm the identity of one of the killer, “Eric Harris, 5’10”, thin build, shaved blond hair, black pants and white T-shirt, light blue gym backpack.”

11:56 a.m.

  • Harris and Klebold come back down the stairs and return to the cafeteria. Klebold is holding a TEC 9, a blowback-operated semi-automatic pistol.

11:57 a.m.

  • The shooters are seen on cafeteria video standing in the cafeteria looking over the damage.
  • They then walk back toward the kitchen.

11:59 a.m.

  • The two aimless men leave the kitchen area and head upstairs to the library.

12:02 p.m. – 12:05 p.m.

  • Paramedics from the Littleton Fire Department rescue three students —Sean Graves, Lance Kirklin, and Anne Marie Hochhalter—as they lay wounded outside the cafeteria. Dan Rohrbough was dead and left behind.
  • Gunfire hails down from the second-storey library windows above the cafeteria as paramedics rescue wounded students.
  • Police return gunfire.

Photo: www.youtube.com/watch?v=Xm1-lI51QZY

12:08 p.m.

  • After the last gunshot is fired from the library window, Harris and Klebold commit suicide.
  • A smoke alarm in the library goes off at 12:08 p.m., above where their bodies are eventually found. A Molotov cocktail was placed on a nearby table. The lit fuse generated enough heat to break the glass bottle, which caused the flammable liquid inside to spill over and make a small fire, setting off the alarm. But it didn’t cause the explosion Klebold and Harris were hoping for. Arson investigators later determine that the fire occurred after the two killed themselves.
  • Their bodies are not found for another three hours.

12:12 p.m.

  • Television reports start to leak out about the Columbine shooting. Information is sparse. Reports are that four or five students are being treated for extensive bleeding.

1:30 p.m.

  • SWAT keeps getting conflicting reports about where the gunmen are. As a result, they end up checking places that are far removed from where the shootings actually took place.
  • They find around 60 students hiding in the closet of the music room, but they are too afraid to come out. Most students saw the black combat fatigues the shooters wore, which look very similar to what the SWAT team is wearing. Eventually, they are convinced it is safe and ushered out of the school.

2:15 p.m.

  • At around this time, and not far from where the SWAT team was evacuating students, a sign appears in the window of the science lab classroom where Dave Sanders lay. “1 BLEEDING TO DEATH.”
  • It was almost three hours since Sanders had been shot.

2:42 p.m.

  • The SWAT team finally reaches Dave Sanders.
  • Students are evacuated immediately, but Sanders is made to wait for a paramedic.
  • Students ask to carry Sanders out but are told “no,” that paramedics are on their way.
  • Two SWAT members wait for paramedics to arrive.

3:24 p.m.

  • Paramedics finally arrive, four hours after Sanders was shot. It is too late; Sanders has already died from blood loss.
  • Sanders’ last words were: “Tell my family I love them.”
  • He is the last of 13 victims to die that day.

4:30 p.m.

  • More than five hours after the massacre began, and four hours and 22 minutes after Harris and Klebold committed suicide, Columbine is officially declared safe.

4:45 p.m.

  • Christopher Colwell, attending emergency room physician at Denver Health Medical Center, and Robert Montoya, a Denver Health paramedic, pronounce Rachel Scott and Daniel Rohrbough as deceased.
  • Colwell takes a second sweep of the library and pronounces each of the 10 victims and two shooters dead.
  • Colwell also goes to the science lab and pronounces Sanders as deceased.
  • The whole school is declared a crime scene. As a result, some of the bodies are left where they fell for two days.

Later that day, President Bill Clinton held a press conference where he said he was “profoundly shocked and saddened about the tragedy” in Littleton.

“To the parents who have lost their beloved children, to the wounded children and their families, to the people of the community of Littleton, I can only say tonight, that the prayers of the American people are with you.”

The next day, thousands of people left flowers and other memorials for those who died at Columbine High School on April 20, 1999.