During the investigation of this case, several sources were utilized in compiling an accurate chronological timeline of the many different events that occurred at Columbine High School on April 20, 1999. This included dispatch and 911 tapes from the Jefferson County Sheriff's Office, dispatch tapes from the Littleton Fire Department, several newscasts from local media, the record of the school fire alarm system and the cafeteria surveillance videotape from Columbine High School.
During the first two weeks of the investigation, investigators learned that the Jefferson County Sheriff's Office had recently calibrated its digital clocks used for dispatch tapes with the National Institute of Standards and Technology (NIST) atomic clock in Boulder, Colorado.Therefore, the Jefferson County Sheriff's Office dispatch time was the standard used for the timeline.It was further learned that the Sheriff's Office 911 times had not yet been calibrated and were fast by two minutes and 46 seconds.The Littleton Fire Department dispatch time was four minutes slow and the fire alarm from Columbine High School was three minutes slow. The times on the cafeteria videotape matched the Sheriff's Office dispatch time.
In order to accurately reflect the events occurring on April 20, it became necessary to adjust the times so that they were synchronized to one time -- in this case, the Jefferson County Sheriff's Office dispatch time. The following changes were made and are reflected in the finished timeline:
- 4 minutes were added to the Littleton Fire Department dispatch time
- 3 minutes were added to the school fire alarm time
- 2 minutes 46 seconds were subtracted from the Jefferson County 911 time
- No adjustments were made to the high school cafeteria surveillance tape.
11:10 a.m.
On the last day of his life, Eric Harris arrives alone at the student parking lot at Columbine High School and parks his 1986 gray Honda Civic in a space assigned to another student in the south junior parking lot.
Dylan Klebold subsequently arrives at the high school student parking lot alone in his 1982 black BMW. He parks in a space assigned to another student in the southwest senior lot. Klebold's and Harris' cars flank the school's cafeteria and the exits and entrances into the lower level.
Harris speaks to one student briefly outside the west entrance of the school. According to the student, Harris tells him to leave the school because he likes him. Shortly thereafter, the same student is seen by witnesses walking south on Pierce Street away from the area. This student is the only person Harris and Klebold direct away from the school grounds moments before the killing begins.
11:14 a.m.
Between 11:14 a.m. and 11:22 a.m. Harris and Klebold leave their cars and walk into the school's cafeteria, carrying two large duffel bags containing enough explosive power to kill the majority of the students who soon would be arriving for 'A' lunch. The gunmen place the bags on the floor beside two lunch tables and walk back out.
Blending in with 400 other backpacks and bags scattered throughout the cafeteria, the duffel bags conceal 20-pound propane bombs timed to explode at 11:17 a.m. Harris earlier had determined that 11:17 a.m. was the exact time for the high school cafeteria to be packed with the maximum number of students possible.
The school custodian goes into the video room to change the school's cafeteria surveillance videotape.
After placing two 20-lb. propane bombs in the cafeteria, Harris and Klebold go back out to the student parking lots to sit in their respective cars and wait for the bombs to explode.
From their cars, they have a clear view of the cafeteria area. Based on comments Klebold and Harris made in their homemade videotapes, the investigation determined the two planned to shoot any surviving students able to escape from the cafeteria after the bombs exploded.
Klebold and Harris also have bombs constructed with timers in their cars, set to go off once they go back into the school.
11:19
Jefferson County Dispatch Center receives the first 911 call from a citizen reporting an explosion in a field on the east side of Wadsworth Boulevard between Ken Caryl and Chatfield Avenues. The explosion is actually a timed diversionary device. Two backpacks with pipe bombs, aerosol canisters and small propane tanks had been placed in a grassy open space three miles southwest of Columbine High School. Only the pipe bombs and one of the aerosol canisters explode but the explosion and subsequent grass fire are enough to get the attention of the Jefferson County Sheriff's Office and the Littleton Fire Department. The bombs exploding in the field along Wadsworth Boulevard are intended to divert the attention of law enforcement away from what is planned to be a much more devastating scene at the school.
11:19 to 11:23
Several witnesses identify Harris and Klebold standing together at the top of the west exterior steps, both wearing black trench coats and carrying a backpack and duffel bag. That location is the highest point on campus and allows them an elevated vantage point of the school's west side, the southwest senior parking lot and portions of the junior lot, the cafeteria exits and entrances, and the athletic fields to the west.
At about 11:19 a.m. a witness hears one of the suspects say, "GO! GO!" Klebold and Harris then pull their shotguns out of their bags. They already have 9-mm semi-automatic weapons hidden under their coats. From their position at the top of the steps they begin shooting at students in the area. Thus begins what is now known as the worst U.S. school shooting in history.
The first gunshots, fired toward the west doors, kill Rachel Scott and injure Richard Castaldo, students at Columbine High School. Rachel and Richard had been sitting on the grass eating their lunch outside the school's west upper entrance near the north side of the library.
Students Daniel Rohrbough, Sean Graves, and Lance Kirklin, having just come outside through a side door of the school cafeteria on their way to the "Smoker's Pit" at Clement Park, are hit by gunfire. All three fall to the ground.
Five students, sitting on the grass to the west of the stairs, are shot at as they begin to run from the melee. Michael Johnson suffers gunshots wounds but is able to reach the outdoor athletic storage shed where he takes cover with others. Mark Taylor suffers a debilitating gunshot wound and falls to the ground, unable to flee with the others.
Klebold goes back down the stairs to the area outside the cafeteria and shoots Daniel Rohrbough again at close range, killing him instantly. He also shoots Lance Kirklin again, this time at close range, but Lance survives.
Klebold briefly enters the side entrance to the cafeteria and stands just inside the doorway, perhaps to discover why the propane bombs have not exploded. He then goes back outside and joins Harris at the top of the outside stairs.
Harris shoots down the stairs hitting Anne Marie Hochhalter. Anne Marie is shot multiple times as she stands to run for cover into the cafeteria.
Witnesses hear one of the gunmen shout, "This is what we always wanted to do. This is awesome!"
From the onset, both suspects are seen lighting and throwing explosive devices onto the roof, into the parking lot and toward the grassy hillside.
11:21
Deputy Paul Magor, a Jefferson County Sheriff's deputy patrolling the south Jeffco area, is dispatched to the scene of the fire and explosion on Wadsworth Boulevard.
11:22
The school custodian, after rewinding a recycled videotape, hits the record button on the VCR that records images of lunchtime activities in the school cafeteria. The tape immediately shows students near the windows beginning to notice something happening outside and some start toward the cafeteria windows to look.
Jefferson County Sheriff's Deputy Neil Gardner, community resource officer at Columbine High School, has just finished his lunch while sitting in his patrol car at the students' "Smoker's Pit" when he receives a call from the school custodian on the school's radio. He's needed in the "back lot" of the school.
11:23
A 911 call from a Columbine High School student reports a girl injured in the south lower parking lot of the high school. "I think she's paralyzed,î the caller tells dispatch.
Deputy Magor, on his way to the explosion in a field off Wadsworth, is advised of a female down in the south parking lot of Columbine High School.
Deputy Gardner, pulling his car onto Pierce Street and heading south to the student parking lot, hears the same call, this time coming over the Sheriff's radio, "Female down in the south lot of Columbine High School.î He activates his lights and siren.
11:24
Several of the school's custodial staff and faculty, including teacher William "Dave" Sanders, are attempting to find out what is happening outside the school cafeteria.
Realizing a danger, Sanders and school custodians Jon Curtis and Jay Gallatine enter the cafeteria and direct students to get down. Students begin to hide under the cafeteria tables.
Deputy Paul Smoker, a motorcycle patrolman for the Jefferson County Sheriff's Office, is writing a speeding ticket on West Bowles Avenue, just west of Pierce Street, when he hears dispatch report that a female is down in the south lower lot of Columbine High School. Smoker's traffic stop is just north of the school so he radios dispatch that he is responding to the school.
Teacher Patricia (Patti) Nielson is working as a hall monitor when she hears a commotion outside the west entrance of the school. She looks outside, seeing two male students with what she thinks are toy guns, and assumes that a school video production is being taped. She is on her way outside to tell the boys to "knock it off" when one of the gunmen fires into the west entrance, causing glass and metal fragments to spray into the hallway. Nielson suffers abrasions to her shoulder, forearm and knee from the fragments.
Beside Nielson is student Brian Anderson. Brian had been told by a teacher to get out of the school because of the explosions and commotion. Not realizing where the danger is, he exits through the first set of west doors, and is caught between the interior and exterior doors when Harris fires at the doors in front of him, shattering the glass. Brian suffers wounds to his chest from the flying glass fragments.
Despite their injuries, Patti Nielson and Brian are able to flee into the school library while Harris and Klebold are distracted by the arrival of Deputy Gardner. Gardner has just pulled up in the lower south parking lot of the school with the lights on his patrol car flashing and the siren sounding.
As Gardner steps out of his patrol car, Eric Harris turns his attention from shooting into the west doors of the high school to the student parking lot and to the deputy. Gardner, particularly visible in the bright yellow shirt of the community resource officer's uniform, is the target of Harris' bullets. Harris fires about 10 shots at the deputy with his rifle before his weapon jams.
Gardner fires four shots at Harris.
Harris spins hard to his right and Gardner momentarily thinks he has hit him. Seconds later, Harris begins shooting again at the deputy. Although Gardner's patrol car is not hit by bullets, two vehicles that he is parked behind are hit by Harris' gunfire. Investigators later found two bullet holes in each of the cars.
Harris then turns and enters the school through the west doors.
Students in the cafeteria realize the activity occurring outside is more serious than a senior prank. A mass exodus of students is seen on the school's surveillance videotape as students escape up the stairs from the cafeteria to the second level. Several students recalled Sanders directing them to safety by telling them to go down the hallway to the east side exits of the school.
11:25
Jefferson County Sheriff's Office dispatch advises that there are possible shots fired at Columbine High School. "Attention, south units. "Possible shots fired at Columbine High School, 6201 S. Pierce, possibly in the south lower lot towards the east end. One female is down."
Teacher Patti Nielson, hiding under the front counter in the school library, calls 911 to report shots being fired outside the library.
11:26
Littleton Fire Department dispatches a fire engine to the explosion and grass fire on Wadsworth.
After exchanging gunfire with Harris, Gardner calls on his police radio for additional units. "Shots in the building. I need someone in the south lot with me."
Dispatch reports several shots fired at Columbine High School.
Teacher's 911 call from inside the library reports smoke coming in through the doorway. She yells at students to get on the floor and under the tables.
Jefferson County Deputies Scott Taborsky and Paul Smoker arrive on the west side of the school and begin the rescue of two wounded students lying on the ground near the ballfields.
Smoker sees Gardner down the hill to his right, holding a service pistol. Gardner yells to Smoker as a gunman, carrying a semi-automatic rifle, appears on the inside of the double doors.
Harris, leaning out of a broken window on the set of double doors into the school, begins shooting a rifle. Smoker fires three rounds at him and the gunman disappears from the window. Smoker continues to hear gunfire from inside the building as more students flee from the school.
Student witnesses who entered the north main hallway from adjoining classrooms see Klebold and Harris standing just inside the school's northwest entry doors. Both suspects, they later recalled, are armed with guns. Witnesses see Klebold fire a semi-automatic weapon east towards the students in the main hallway and south down the library hallway. They also hear bullets hitting lockers and other objects in the hallway as students run for cover.
A student in the gym hallway observes Klebold and Harris walking east down the north hallway. Both are firing weapons Ö and both are laughing.
Student Stephanie Munson and another student walk out of a classroom into the school's north main hallway. As they enter the hallway, they see a teacher and several students running behind them. The teacher yells for the students to "Run! Get out of the building!î They both run through the main hallway leading to the school's main entrance on the east side. Stephanie is shot in the ankle but both are able to escape the building and continue across the street to safety at Leawood Park.
A student in the counseling hallway sees students in the north hallway running east through the lobby. Klebold is running behind them, but comes to an abrupt halt near a bank of phones at the entrance to the main lobby area.
Yet another student, on the telephone with her mother, glances up in time to see the sleeve of a black trench coat shooting a TEC-9 towards the main entrance of the school. She drops the phone and hides in a nearby restroom until she can no longer hear any activity in the hallway. The gunman, she assumes, has turned around and gone back the other way. She goes back to the phone and whispers to her mother to come pick her up and then escapes through the east doors to the outside. Her mother's cell phone bill shows this call is made between 11:23 and 11:26 and lasts 3.8 minutes. The student estimates that she talks to her mother about two minutes before she sees the gunman.
Klebold is last seen running back down the north hall to the west in the direction of the library hallway.
Teacher Dave Sanders, still on the second level, turns into the library hallway toward the west entrance and the sounds of gunfire. As Sanders passes the entrance to the library, he apparently sees a gunman coming toward him from the north hallway. Sanders turns around and heads back the way he had just come. Just before turning the corner to go east, he is shot. Sanders is able to crawl to the corner of the Science hallway where teacher Richard Long helps him down the hallway into classroom SCI-3. A group of students, including two Eagle Scouts, Aaron Hancey and Kevin Starkey, gather around him, attending to his injuries and administering first aid.
11:27
Deputy Gardner, who is in the south parking lot and has exchanged gunfire with Eric Harris, radios dispatch with a "Code 33.î Code 33 means "officer needs emergency assistance."
Deputy Magor sets up a road block on Pierce Street at the southeast corner of the student parking lot. He immediately is approached by a teacher as well as students reporting a person in the school with a gun.
Dispatch announces that possible hand-grenades have been detonated at the school.
Harris and Klebold walk up and down the library hallway, randomly shooting but not injuring anyone. Investigators later scrutinized Nielson's 911 call made from the school's library. From the tape, the investigation shows that Harris and Klebold spend almost three minutes in the library hallway randomly shooting their weapons and lighting and throwing pipe bombs. They throw two pipe bombs in the hallway and more over the stairway railing to the lower level.
A pipe bomb is thrown into the stairwell from the library hallway and lands in the cafeteria below. A large flash is observed on the cafeteria videotape. A second pipe bomb also is thrown into the cafeteria from the upper level.
Teacher Patti Nielson, hiding under the front counter just inside the library entrance, continues her phone contact with the Jefferson County dispatcher. Nielson reacts to the sounds of gunshots and explosions coming from the hallway outside the library. Interspersed with short conversations with the dispatcher, she screams at the students in the library to get under the tables and to stay hidden. She then reports that a gunman is just outside the library entrance.
11:28
Numerous students, running from the school, seek safety behind Taborsky's patrol car on the school's west side. The students tell the deputies that gunmen are inside the school randomly shooting at people with UZIs or shotguns and throwing hand-grenades. They describe the younger of the two gunmen as possibly high school age and wearing a black trench coat and a hat on backwards. The second gunman is described as "taller, a little older" and also wearing a black trench coat.
Smoker can see other deputies on the west side of the school near the concrete shed and the ballfields.
Dispatch alerts the deputies that the shooter may have a shotgun.
A 911 call reports that students are injured outside the school.
Deputy Smoker radios that students are saying the shooter is wearing a black trench coat.
11:29
Gardner requests emergency medical response to the west side of the school.
Dispatch alerts all units that Deputy Gardner is under fire and the suspect just ran into the building. "Shots fired on the southwest side with a large weapon."
Harris and Klebold walk into the school library. The 911 call records a male voice yelling, "Get up!"
11:29 to 11:36
Harris shoots down the length of the front counter. One student, crouched behind a paper copier, is injured by flying wood splinters from the counter.
The gunmen walk through the library toward the west windows, killing one student on the way, before they shoot out the windows toward law enforcement and fleeing students.
Law enforcement returns the fire.
The gunmen then turn their attention to students inside the library. They kill four and injure four more in the west area of the library before moving back toward the library entrance to the east.
Harris and Klebold shoot out the display cabinet near the front door before firing their guns in this section of the library, injuring five and killing three.
Harris and Klebold leave the library's east area and enter the center section, reloading their weapons at this point.
Two more students are killed and two more injured in the library's center section before the gunmen leave the library.
In 7 minutes, 10 people are killed and 12 more wounded. There are a total of 56 people in the library; 34 escape injury.
Two library employees remain hidden in the television studio. One teacher hides in the periodicals room. Patti Nielson, originally hiding under the front counter, drops the phone. She ultimately crawls into the library's break room to hide in a cupboard. All four women remain in the library until they are evacuated by SWAT around 3:30 p.m.
11:30
Jefferson County Patrol Deputy Rick Searle, on the upper grassy area on the southwest side of the school, is evacuating students who have taken cover behind Taborsky's patrol car. In three separate trips, Searle transports the students, including those wounded, south to a safe location at Caley Avenue and Yukon Street. Medical triage soon will be established at this spot. As soon as he gets back from his evacuation trips, he discovers even more students who have escaped the school and taken cover behind Taborsky's patrol car.
Deputy Kevin Walker, positioned at a southern point in the student parking lot, is able to watch the lower level main south doors of the school and the entrance to the cafeteria. He can provide rescue and cover for the students fleeing to the south from the school's lower level.
Deputy Taborsky reports hearing additional shots being fired inside the school -- "large caliber."
Dispatch reports possible shots fired in the library.
Littleton Fire calls for personnel to stage at the scene. As the department learns that some students fleeing the school are possibly injured, personnel are instructed to stage in several areas nearby and set up triage sites to treat the injured.
The county's dispatch center goes into an emergency command system as the incoming reports begin to provide glimpses of the incident's magnitude. Additional dispatchers soon arrive to help deal with the escalating radio traffic and 911 calls.
11:31
Deputy Searle reports smoke coming from the building.
Deputy Taborsky reports a person down on the southwest side of the school.
The 911 tape from the library records the sound of many gunshots being fired during this minute. One of the gunmen in the library yells, "Yahoo!"
The first fire alarm sounds from the upper level corridor of Columbine High School.
11:32
Deputy Walker reports possibly seeing one of the gunmen through the windows on the upper level, southwest corner. Walker describes him as wearing a "white T-shirt with some kind of holster vest."
As students and faculty escape the school to the south, they report what they saw or experienced to Deputy Magor, whose patrol car is blocking the traffic on Pierce Street to the south. Magor realizes the severity of the escalating situation and radios that the Sheriff's Office needs mutual aid at the scene.
Many agencies already are aware of the situation at the high school because of the radio traffic they are hearing and personnel are quick to arrive at the scene. Several arriving Denver police officers and one Littleton police officer have children who are students at Columbine. One student, hiding with others inside the school's kitchen, is on a cell phone with the Denver Police Department. His father is an officer in the department.
The first call is received by the Sheriff's Office from the media requesting information about what is happening at Columbine High School.
11:33
Jefferson County SWAT commander Lt. Terry Manwaring, on his way to the high school, orders the Jefferson County SWAT team and the Sheriff's Office command staff to be paged.
Dispatch reports a possible shooter on the football field behind the shed.
Jefferson County Dispatch asks if any deputies on scene have a "long gun" (a rifle or shotgun).
In response to Magori's call for mutual aid, Jefferson County Dispatch advises that additional assistance is coming from other agencies.
11:34
Suspects move to the center section of the library.
11:35
Dispatch advises additional gunfire being reported.
Dispatch advises that several SWAT teams are en route.
The last victim is killed at Columbine High School.
Suspects move to the front counter of the library.
11:36 to 11:44 a.m.
From the library Harris and Klebold go into the hallway and make their way to the science area. Witnesses describe the two as looking through the windows of some of the classrooms' locked doors, making eye contact with some of the students, yet not attempting to break into the rooms or harm any more students.
A teacher sees Klebold and Harris in the science hallway, stopping in front of the chemical storage room just east of Science Room 3 where she is hiding.
Several students witness the suspects shooting into empty rooms. Klebold and Harris also tape an explosive device on the storage room door next to the area where teacher Dave Sanders and several students are hiding. Witnesses say the gunmen do not appear to be overly intent on gaining access to any of the rooms. The gunmen easily could have shot the locks on the doors or through the windows into the classrooms, but they do not. Their behavior now seems directionless.
11:36
Deputy Searle reports a man on the roof wearing a red, white and blue striped shirt. Initially thought to be a possible shooter, the man is later identified an employee of a heating and air conditioning company on a service call at the school to fix a leak above the girls' locker room. The repairman is on the roof when the first shots are fired and, when he realizes something is wrong, he uses a pair of vice grips to clamp the roof access hatch closed so nobody can come up to the roof.
Sgt. Ken Ester of the Intelligence Unit reports to the southeast side of the school and assists Deputy Magor.
Several more pipe bombs are thrown into the cafeteria from the library hallway a floor above. Another explosion can be seen at this time on the cafeteria videotape.
Dispatch advises multiple reports of shots in the library and multiple suspects with different descriptions -- the last being "a white, red and blue striped shirt up on the roof."
Jeffco SWAT team commander Manwaring arrives at Pierce and Leawood and advises dispatch that the command post and the SWAT staging area will be set up at that location.
11:37
Another pipe bomb is thrown over the railing from the hallway above and into the cafeteria area where it explodes. This can be heard on the 911 call made from inside the library.
Littleton Fire Department is staged at Weaver and Pierce Streets.
11:38
Deputy Walker, on the south side of the school, reports an explosion that blows out windows near the cafeteria. The explosion is from a pipe bomb.
As the pipe bomb explodes, several students run out of the south cafeteria doors toward Walker. The deputy directs them to take cover behind several cars, covering them with his own gun while they position themselves away from the line of fire. Walker radios to dispatch that he has students with him, but he does not have any safe path to evacuate them from the parking lot.
Dispatch reports that one shooter is in the food preparation area and that the shooter has 17 students in that area with him. In actuality, a 911 call received from a student hiding with 17 others in the school's kitchen reports what he thinks is a shooter in the area. The investigation determined from the cafeteria videotape that several custodial staff, equipped with keys and school radios, were in the kitchen area at that time. The student assumed what he heard were the shooters and reported to dispatch that the shooters had keys to the school and walkie talkies.
11:39
Jefferson County Patrol Sgt. Phil Hy arrives on scene and begins identifying and disseminating pertinent information to the initial responders.
11:40
Deputies report 30 students have exited the school on the west side. Many of these students taking cover behind the patrol cars are those who are able to escape from the school library after Klebold and Harris leave the library and go into the science area.
Deputy Taborsky, protecting students who have fled out the west side of the school, reports that one of the shooters might be "Ned Harris" and that he is possibly wearing bulletproof armor. The witness probably was saying "Reb,î which was Harris' nickname.
Dispatch advises that the suspects are possibly wearing body armor.
Deputy Walker reports more explosions inside the school. The explosions seem to be moving east.
11:41
Deputy Searle reports the man is still on the roof and has moved over to the north side.
11:42 to 11:43
Based on 911 calls coming in, dispatch advises that a suspect has possibly left the building.
Dispatch also reports one person wearing a red and white shirt on the north side of the roof, one suspect in the library with a shotgun and several bombs, and another person in the cafeteria with "bulletproof equipment and several bombs."
11:44
In response to reports that one of the suspects may have left the building, several deputies on scene radio their positions around the school, confirming that a perimeter has been established and all exits are covered by law enforcement.
1. Jefferson County Deputy Bob Byerly reports that he and members of the Colorado State Patrol (CSP) are on the northeast side of the school by the tennis courts. He maintains a view of the north side of the school and the northeast doors.
2. Deputies Taborsky and Smoker are on the southwest, protecting and evacuating numerous students escaping out the west side.
3. Deputy Searle is on the northwest side of the building, assisting with evacuation and transportation of students and staff.
4. Sgt. Ester and Deputy Magor are on the southeast side, assisting students and diverting traffic away from the area.
5. Deputy Neal Schwieterman is on the west side by the ballfields and athletic shed, assisting with transporting students to triage and to safety.
6. Deputy Walker is protecting and evacuating students on the south side.
Klebold and Harris leave the science area and go down into the cafeteria. The cafeteria videotape records Harris kneeling down and resting his rifle on the stair railing and firing several shots at one of the large 20-pound propane bombs hidden in a duffel bag. Photos of the cafeteria show duffel bags and backpacks scattered throughout the area, yet Harris seems to know exactly where the bombs are located and in what bags. He apparently shoots at the one, presumably in an attempt to make it explode. It does not.
The videotape also shows Klebold walking directly over to the same bomb after Harris' failed attempts to detonate it. Klebold seems to be tampering with something on the floor.
The suspects both take a moment to drink from water bottles left by students on the school lunch tables.
A witness hiding in the cafeteria hears one of the gunmen say, "Today the world's going to come to an end. Today's the day we die."
11:45
Harris and Klebold walk toward the food serving line in the cafeteria area.
Klebold throws something in the vicinity of the propane bomb.
Lt. Dave Walcher of the Jefferson County Sheriff's Office arrives on scene. Walcher assumes the role of incident commander.
11:46
Harris and Klebold are in the cafeteria about 2 minutes.
The cafeteria videotape shows that, as the gunmen are walking away, there is a partial detonation of a bomb and a subsequent fire. The bomb is attached to smaller containers of flammable liquids that may have been ignited by a device thrown by Klebold. That explosion causes the fire in the cafeteria that, in turn, moments later activates 5 fire sprinklers in the area. These events are recorded on the cafeteria's surveillance cameras. The large 20-lb propane tank and the second complete bomb/duffel bag beside a nearby table do not explode.
Deputy Searle, outside the building, reports a fire in the cafeteria.
Four students run out of the cafeteria through a side door.
11:47
One student can be seen on the cafeteria videotape crawling out of the cafeteria side door.
One gallon of fuel ignites in the area of the partially detonated propane bomb.
Dispatch advises of reports of two suspects with UZIs, pipe bombs and shotguns.
During its late morning news program, Denver's KMGH-TV Channel 7 announces that Jefferson County has confirmed gunshots fired at Columbine High School.
11:49
Suspects are in the office area.
Sgt. Ester reports that Denver Metro SWAT has arrived on the east side of the school.
11:51
The 911 call made by Patti Nielson from the library is terminated by the dispatch center since no more activity could be heard on the line.
11:52
Jefferson County Undersheriff John Dunaway arrives at the command post and authorizes SWAT to make an immediate entry into the school.
Deputy Byerly reports shots fired on the east side of the building.
The fire sprinkler system alarm in the cafeteria is activated.
11:53
Jefferson County Sheriff John Stone, on his way to Columbine High School, calls Jefferson County Commissioner and Board Chairman Patricia Holloway. He alerts her that gunshots are being fired at the south Jefferson County school and there are reports of students injured and possible hostages taken.
Dispatch informs the command post that bomb squads from the Jefferson County and Arapahoe County Sheriff's Offices are en route.
Dispatch also confirms a live bomb at Wadsworth and Chatfield. "Repeat. A live bomb at Wadsworth and Chatfield."
11:53 to 11:55
Law enforcement officers on the east side of the school report noises and shots coming from the school's northeast side.
Searle reports that Denver Police Department personnel are at the shed on the west side of the school and they have "long guns."
A two-hour 911 phone call (from 11:29 a.m. to 1:24 p.m.) from a school secretary and a school security officer hiding in the school's main office reports shots fired in the office, into the ceiling and in the art hallway to the north.
Dispatch gives the command post a description of one of the suspects: "Eric Harris, 5'10", thin build, shaved blond hair, black pants and white T-shirt, light blue gym backpack."
Littleton paramedics transport student Stephanie Munson, shot in the ankle while escaping out the east main entrance, to Littleton Hospital.
11:56
Klebold and Harris' movements continue to be extremely random. The cafeteria videotape shows the gunmen coming back down the stairs and into the cafeteria. Klebold is holding the TEC 9.
Television news announces reports of two gunmen at Columbine High School.
Deputy Smoker advises dispatch that four down on the west side need to be evacuated.
11:57
Two ambulances, responding to Gardner's call for medical assistance on the south side, approach the south parking lot.
Walker reports shots fired from inside the school.
The cafeteria videotape shows Klebold and Harris standing in the cafeteria surveying the damage.
The suspects walk back toward the kitchen area.
Deputy Schwieterman reports an ambulance has arrived on the south side.
11:58
Schwieterman, positioned by the west side athletic shed, reports that there are five victims outside on the southwest side of the school and gives directions where ambulances should come into the area to rescue them.
Littleton Fire Department announces that its command post is set up at Leawood and Pierce.
11:59
The suspects leave the kitchen area.