The Columbine High School Shootings

    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. [it is astounding to me that all the times were not frequently adjusted to the atomic 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 two boys 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.


    ·         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 – 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 boys say, “GO! GO!” Klebold and Harris then pull their shotguns out of their bags.  They already have 9-mm semiautomatic 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 (d01) and injure Richard Castaldo (w01), 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 (d02, only wounded this first time), Sean Graves (w02), and Lance Kirklin (w03, first time), 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 away. Michael Johnson (w04) suffers gunshots wounds but is able to reach the outdoor athletic storage shed where he takes cover with others. Mark Taylor (w05) suffers a debilitating gunshot wound and falls to the ground, unable to flee with the others. (w06)(w07)(w08)

    ·         Klebold goes back down the stairs to the area outside the cafeteria and shoots Daniel Rohrbough (d02, killed this second time) again at close range, killing him instantly.  He also shoots Lance Kirklin (w03, second shooting) 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 (w09).  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 attackers are seen lighting and throwing explosive devices onto the roof, into the parking lot and toward the grassy hillside. 


    ·         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           Deputies on their way to the Scene

    ·         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,” 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.” He activates his lights and siren.


    ·         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 (w10) 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 (w11). 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.


    ·         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      Hallway Events - Part 1 

    ·         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 semiautomatic 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 semiautomatic 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 … and both are laughing.

    ·         Student Stephanie Munson (w12) 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!”  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, (d03, 3rd shot to death, but last to die, 4 hours later, of blood loss) 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.


    ·         Deputy Gardner, who is in the south parking lot and has exchanged gunfire with Eric Harris, radios dispatch with a “Code 33”  meaning “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.


    ·         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.


    ·         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 – 11:36      Library

    ·         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. (w13)

    ·         The gunmen walk through the library toward the west windows, killing one student on the way (d04), 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 (d05)(d06)(d07)(d08) and injure four more (w14)(w15)(w16)(w17) 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 (w18)(w19)(w20)(w21)(w22) and killing three (d09)(d10)(d11). 

    ·         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 (d12)(d13) and two more injured (w23)(w24) in the library’s center section before the gunmen leave the library. 

    ·         In 7 ½ 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 15:30.


    ·         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.  


    ·        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!”

    11:32         Communications Problems

    ·         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.  


    ·         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 Magor’s call for mutual aid, Jefferson County Dispatch advises that additional assistance is coming from other agencies.  


    ·         Suspects move to the center section of the library.


    ·         Dispatch advises additional gunfire being reported.

    ·         Dispatch advises that several SWAT teams are en route.

    ·         The last victim (d14) is killed at Columbine High School.

    ·         Suspects move to the front counter of the library.

    11:36 – 11:44 a.m.        in the science area

    ·         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       Command Post formed

    ·         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.

    ·         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        Hallway Events - Part 2 

    ·         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.


    ·         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.


    ·         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,” 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.


    ·         Deputy Searle reports the man is still on the roof and has moved over to the north side.

    11:42 – 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         Cafeteria

    ·         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.

    ·         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 gunmen 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."

    There were four surveillance cameras that captured the activity inside the cafeteria and recorded the events on tape.  


    ·         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 ½ 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. Four students run out of the cafeteria through a side door.  



    ·         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.


    ·         Suspects are in the office area.

    ·         Sgt. Ester reports that Denver Metro SWAT has arrived on the east side of the school.


    ·         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        County Support

    ·         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 – 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 . to 13:24) 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.


    ·         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.


    ·         Walker reports shots fired from inside the school.

    ·         The cafeteria videotape shows Klebold and Harris standing in the cafeteria surveying the damage. 

    ·         They walk back toward the kitchen area. 


    ·         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.


    ·         The suspects leave the kitchen area.  

    12:00 --   Klebold and Harris leave the cafeteria and go upstairs to the library.
    --   The command post tells dispatch to request Channel 7’s news helicopter flying overhead to land in Clement Park in order to pick up a Sheriff’s deputy for an aerial survey of the school.
    -- An armored vehicle is requested to rescue the injured because the scene is “not safe for medical.”
    --   Uninterrupted media coverage about the shooting in progress at Columbine High School begins on local television channels.
    12:02 --  SWAT commands use of a Littleton fire truck to provide cover as the first Jefferson County, Littleton and Denver SWAT officers approach the school. Deputy Del Kleinschmidt, a Jefferson County K-9 team member assigned to SWAT, volunteers to drive the truck.
     12:03 --  A television reporter interviews the mother of a student who told her about gunmen dressed in black in the high school’s commons area.  The station also reports that, according to information gleaned from its police scanners, the school is being evacuated.
    12:02 – 12:05 --  Littleton Fire Department paramedics rescue Sean Graves, Lance Kirklin and Anne Marie Hochhalter as they lay wounded outside the cafeteria.  Because the scene is not safe, law enforcement deputies and officers move in closer to provide cover for paramedics as they retrieve the victims. 
    --  Gunfire erupts from the second story library windows above the cafeteria as the paramedics rescue the wounded students outside. 
    --  Deputy Walker sees a muzzle flash from a library window and returns fire. --  Deputy Gardner fires three shots at the gunmen.
    -- Denver police officers also provide suppression fire to the library windows.  This allows the paramedics to retrieve the three wounded teens.  The fourth student, Dan Rohrbough, is determined to be dead.  The paramedics rush the living to medical attention.
    --  After the ambulances leave the scene with the wounded, the gunfire coming from the library windows ceases. No gunshot attributed to the gunmen is heard again. 
    --  Gardner turns his attention to a group of 15 students huddled behind a vehicle in the parking lot just a car away from him. One at a time, he evacuates the students down the line of cars to the protection of the last car farthest away from the school and the shooters.  --  Other students begin to escape, some out a side door of the cafeteria, and the officers “leapfrog” them back to Gardner or other waiting deputies.
    --  A television news helicopter begins broadcasting aerial images of Columbine High School.
    --  Jefferson County crime lab is en route to the scene with its mobile crime laboratory unit.
    12:06 --   The first SWAT team, on foot behind a Littleton fire truck, arrives at the east main entrance to the school. Manwaring, leading the ad hoc team, splits the group into two teams and directs Jefferson County SWAT Deputy Allen Simmons to take his team into the school. It is estimated that at 12:06 p.m., Simmons’ team of five officers enters Columbine High School through the southeast doors. Manwaring will lead the second team, using the fire truck as a shield, to the west side where students are reported “down” and gunfire occurring.
    ·      Television news coverage broadcasts images of the SWAT team outside the high school.
    ·      Student Anne Marie Hochhalter is transported to Swedish Medical Hospital.
    ·      Dispatch advises that a victim shot in the head is at the Caley/Yukon triage area.  
    12:07 --   Deputy Walker asks dispatch to check on the man on the roof.
    12:08         The deaths of Klebold and Harris --   Shortly after that last gunshot is fired from the library window at law enforcement and paramedics, Harris and Klebold kill themselves.
    12:10 ·        Medical triage is officially established at Yukon Street and Caley Avenue southwest of the school at the south entrance to Clement Park.  Law enforcement had already transported numerous students to the area as they were evacuated from the school’s south and west sides. One patient is transported by Air Life and several are transported by ambulance from this area.  A second triage and treatment area is set up on the east side of the school after the command post is informed the remaining victims will be brought from inside the school out the east side.
    12:11 --   The heating and air conditioning repairman, initially thought to be a possible sniper, is removed from the roof.
    12:12 ·        A television reporter positioned at the Yukon and Caley triage area describes the scene as a “very bad situation.”  He tells the television audience that four or five students are currently being treated and some are bleeding extensively. ·        Sean Graves, critically injured outside the cafeteria, is transported to Swedish Medical.
    12:14 --   Dispatch tells the command post that a dispatcher is still on the line with students who say that there are suspects in “Rooms 1, 2 and 3”  and several parties are shot, including one faculty member.
    ·      The Jefferson County, Denver and Arapahoe County bomb squads begin to arrive and stage in the parking lot at Clement Park north of the school.  As the incident progresses, bomb technicians from Littleton Fire, Bureau of Alcohol, Tobacco and Firearms (ATF) and the Federal Bureau of Investigation (FBI) join the initial bomb squads.  A total of 16 bomb technicians share in the initial response, some sent to evaluate the construction of the divisionary device, others sent to the homes of the suspects, still others providing safety information to the responders, and many later entering the school to deactivate and/or remove the explosives.
    12:15         The Victim Services Response  --   Sgt. Hy, at the command post on Pierce, reports a possible shooter and hostages at the front door of the school.
    ·      Moments later a lone student comes out of the main doors and runs to the fire truck.  The teen is quickly checked for weapons and injuries, then picked up and put in the back end of the truck’s cab.  The boy reports that no other people are in the office area.
    ·      A news helicopter lands at Clement Park.  Jefferson County Sheriff’s Sgt. Phil Domenico is put on board and uses the helicopter’s camera system to survey the school’s roof.  He remains in the helicopter for the next several hours surveying the area.
    ·      The Jefferson County administrator, emergency management coordinator and public information officer arrive at the Sheriff’s Dispatch Center to offer assistance.  They soon are asked to help field the escalating media calls as the word of the Columbine shootings begins to spread worldwide. County Commissioners Pat Holloway and Rick Sheehan arrive at the dispatch center soon after the county staff.
    ·      The Victim Services Unit of the Jefferson County Sheriff’s Office reports to the command post.  Personnel are assigned to Columbine Public Library to provide services to the students and parents collecting there.  By 12:45, additional counselors and volunteers respond to Leawood Elementary School where high school students and parents are also gathering.
    12:17 --   Deputy Byerly reports that a male wearing a white shirt and black pants is walking on the west side of the school.  The young man had heard of the shooting on TV and ran through Clement Park towards the school carrying an unloaded .22 Caliber rifle and a knife in order to “help the police.”  He subsequently is contacted at gunpoint.  Deputies determine that the individual is not involved in the incident.
    12:18 --   Medical personnel at the Yukon/Caley triage area report four critical, four serious and three stable patients and request 10 ambulances and one helicopter.
    12:19 --   Deputy Walker reports that he has six students with him.
    12:20 --   A student being interviewed on air by a television reporter says that the gunmen shot one of his friends.  He recognizes the shooters as Columbine students and members of the “Trench Coat Mafia” but does not know their names. He also reports that there may be two or three shooters and they have pipe bombs, sawed-off shotguns, and automatics.
    12:21 ·      Lance Kirklin, shot outside the cafeteria during the first few minutes of the shooting rampage, is transported to Denver Health Medical.
    12:22 --   The Air Life helicopter lands in Clement Park in preparation to transport critically wounded to area hospitals.
    12:25 --   Mark Taylor is transported to University Hospital.  Mark was injured outside as he and a group of friends sat on the grassy hill to the west of the stairs where Klebold and Harris first began their shooting rampage.
    ·      Dispatch advises that parents are to go to Leawood Elementary School.  Law enforcement and victim advocates will assist in coordinating the reunion of parents and children at the elementary school.

    12:26 --   Mike Johnson is transported to St. Anthony’s Hospital. Mike was shot as he fled the grassy hill to the west of where Klebold and Harris first began shooting.
    ·      The news reports that there are possibly two gunmen and eight victims at Columbine High School.
    12:27 --  12:27 Jeanna Park (w05) is transported to Denver Health Medical. Kacey Ruegsegger (w06) is transported to St. Anthony’s.  Both girls had been injured by gunfire in the library.  All of those who escaped the library ran out of the emergency exit next to the west entrance to the school.  They ran to Deputy Taborsky’s patrol vehicle and hid behind it until Deputy Searle and several Denver officers were able to load the students in their vehicles.  The officers then transported the students either to Deputy Schwieterman at the shed by the ballfields or directly to triage.
    12:31 --   Lt. Manwaring reports that his SWAT team is on the north side of the school with the fire truck, working its way toward the west side.
    ·      Valeen Schnurr is transported to Swedish Medical with gunshot wounds.  Valeen was in the library at the time of her injuries and was able to escape through the library’s emergency exit when Klebold and Harris left the library.
    12:34 - 12:39 --   Manwaring’s SWAT team reports that it is now on the west side at the back entrance, upper level.
    ·      The first objective of Manwaring’s team is to rescue two students lying in front of the west doors.  Using the fire truck as a shield, the team of Jefferson County and Denver SWAT officers inch the truck as close to the west doors as possible. 
    ·      Two Denver SWAT members rescue student Richard Castaldo from the area in front of the west doors and lay him on the bumper of the fire truck.
    ·      Jefferson County Deputy Scott Taborsky puts Richard in his patrol car and rushes him to medical assistance.
    ·      The SWAT team makes a second approach to the area outside the west doors, this time to retrieve Rachel Scott. They bring Rachel to the fire truck and determine that she has already died. 
    ·      The team makes a third approach, this time in an attempt to rescue the boy at the bottom of the stairs.  They return without him, acknowledging that Daniel Rohrbough is dead.
    12:39  --  Dispatch announces that the Jefferson County Sheriff's mobile command bus is on scene and activated.  
    ·      Manwaring’s SWAT team requests a floor plan of the school.
    12:40 --   Dan Steepleton (w17) is transported to Littleton Hospital.
    --   Information is received that a natural gas leak is occurring in the school.  A decision is made to have Public Service Company shut off the gas as soon as it is considered safe to approach the main valve.  A crew from PSC is present and is notified to be ready to accompany officers into the school when possible.
    12:41 --   Additional SWAT from Jefferson County arrive at the command post on Pierce Street. This team of 10 is commanded by Sgt. Barry Williams.
    ·      Reports being relayed to the command post include possible multiple shooters, a hostage situation, and gunfire and explosions in nearly every wing of the school building. 
    ·      Students on cell phones inside the school are calling out – to 911, their parents, and several times to local television stations.
    ·      Students calling from their cell phones report hearing shots inside the school and give numerous locations for the gunshots, including the gymnasium, the auditorium, the business wing, the music rooms, the science area and the business offices.
    12:43 --   Deputy Simmons, leader of the first SWAT team that entered the 23'000-square-meter school, requests additional SWAT for the east side. Due to the size of the school, the numerous rooms and hallways that have to be searched, and the number of students and faculty being rescued, Simmons calls for more assistance.
    12:44 --   Makai Hall (w18) is transported to Littleton Hospital.  He is later transported to St. Anthony’s Hospital by Air Life.
    ·      Dispatch reports cover fire by Denver Police Department, most likely during SWAT’s rescue of Richard Castaldo at the school’s upper west entrance.
    ·      Dispatch reports that an EMT dispatcher is on the phone with a party inside the school.  The individual is with a critically injured victim.
    12:50 – 13:09 --   Two SWAT deputies are positioned on rooftops of houses on West Polk Avenue, the first neighborhood street just south of the school. From their vantage point, the marksmen have a clear view of the south parking lot, the library windows and the cafeteria area.
    ·      Williams’ SWAT team utilizes a front-end loader parked near the command post to move around the school to the west side.
    ·      Using the front-end loader as cover, Williams’ team first moves into position on the northwest corner of the school, opposite from where Simmons’ SWAT team had entered the building. 
    ·      Williams is advised that students have been shot and numerous bombs have exploded.  The number of suspects, still in the building, is unknown but reports indicate as many as eight. 
    ·      Williams’ team is also told that activity has been reported in both the cafeteria and the library.
    ·      A “live” bomb blocks the outside west doors leading into the upper level hallway and entrance to the library.  The closest point of entry is into the cafeteria directly underneath the library. 
    ·      A window into the teachers’ lounge next to the cafeteria will provide an entry point for Williams’ team. 
    ·      Nicole Nowlen (w19) is transported to Lutheran Medical Center.
    12:51 --   Media reports that several area schools are in “lock down.” Schools are locked from the inside and, for safety reasons, “no one goes out and no one goes in.”
    12:57 --   Austin Eubanks (w08) and Jennifer Doyle (w20) are transported to Littleton Hospital.
    13:00 --   The Jefferson County Critical Incident (Shoot) Team is activated.
    13:03 --   Nick Foss (w22) is transported to Littleton Hospital.
    13:04 --   Richard Castaldo, rescued by SWAT from the outside upper west entrance, is transported to Swedish Medical Center.
    13:09 --   Williams’ team breaks an outside window to gain entrance into the teachers’ lounge.  The team is met with the deafening noise of fire alarms, the flash of strobe lights, ceiling tiles hanging at odd angles and three inches of water coming in under the closed door to the cafeteria.  The alarms and the sprinkler system have been set off by the explosions and the cafeteria area and adjacent rooms are flooding.  Another concern is “a hissing sound and the sound of something spraying.”  Williams fears it might be a broken natural gas line.
    ·      Williams’ team first clears the kitchen and back storage areas, evacuating groups of students and staff hiding behind locked doors.
    ·      Air Life transports Mark Kintgen (w23) from the Yukon/Caley triage to Denver Health Medical.
         13:10 ·        Investigators are at or en route to area hospitals as injured victims are being transported.
    13:11 --   Brian Anderson is transported to Lutheran Medical Center.
    ·      The medical triage at Yukon and Caley reports that all injured have been transported to area hospitals.
    13:15 --   Investigators arrive at the Harris and the Klebold residences.
    13:18 -- Simmons’ SWAT team evacuates 30 students and faculty from south classrooms on the upper level.
    13:22 --   SWAT teams continue a search and rescue inside the school building. Simmons’ team works east to west on the upper level, and Williams’ team works west to east on the lower level.
    ·      Dispatch reports that Arapahoe SWAT team is on scene and ready to assist when needed.
    13:26 --   Williams’ team evacuates numerous students and staff from the back storage rooms and kitchen area.  The students are evacuated out the same window that provided entry for the SWAT team.  

    13:32 --   The cafeteria videotape shows Williams’ SWAT team entering the main cafeteria area, commonly referred to as the “commons.”  The team had just finished clearing and evacuating students and staff from the teachers’ lounge, kitchen area and back storage areas.
    ·      Williams is advised by radio that there are possible bombs throughout the school.  He is told the bombs may be hidden in backpacks and constructed with timers and motion-activated devices.  The information is relayed from bomb technicians who have inspected the diversionary bombs placed on Wadsworth and realize similar devices may have been placed inside the high school.
    ·      Williams’ team is advised that the suspects’ last known location was downstairs by the business classrooms. This information was relayed by a student on a cell phone inside the school.
    13:40 --   Air Life transports Makai Hall from Littleton Hospital to St. Anthony’s Hospital.
    13:44 --   Three male subjects, appearing in a field north of the high school in Clement Park, are contacted by Jefferson County Sheriff's deputies and detained for questioning.
    ·      The three are dressed in black clothing, which matches the known description of the shooters, and are spotted in an unsecured area close to the school.
    ·      These individuals, who are not Columbine students, identify themselves as the “Splatter Punks” and insist they have shown up at Columbine High School mainly out of curiosity. 
    ·      The images of the three being taken into custody by law enforcement authorities, aired live on local television channels, raised numerous questions from the community about their involvement in the crime. 
    ·      After initial questioning, the three youths are released the same afternoon and are re-interviewed at length on April 24.  It is determined that they had no known affiliation with the Trench Coat Mafia, and, shortly thereafter, are cleared of any involvement.
    13:57 --  Williams’ SWAT team announces that it has found several students and faculty hiding in the ceiling of the kitchen. Six individuals are evacuated out the west side.
    ·      Dispatch tells Williams there is a male upstairs “in the library past the stairs” doing CPR on an injured party.  The SWAT team is also told that a blue and white shirt is hanging on the door knob.
    13:59 -- Williams asks for better directions on how to get to the injured party.
    14:08 --   Students are evacuated from the Technology Lab on the main floor.
    14:12 -- The Lakewood SWAT team, with an armored vehicle, approaches the west side of the school next to the south parking lot.
    ·      SWAT positioned on the roof of a residence to the south of the school reports a sign in a window on the upper level.  The sign reads, “1 bleeding to death.” 
         14:17 --   Williams splits his team and half clears the computer and business classrooms on the lower level southeast of the cafeteria. They evacuate two people found in the furthest business classroom out the south side.
    14:19 ·        A Columbine parent, waiting at Leawood Elementary for word about his son, is transported to Littleton Hospital because of chest pains.  He is one of many parents in anguish awaiting word of their children.
    14:24 --   Adam Kyler (w13) is transported to Littleton Hospital.
    ·      The second half of Williams’ SWAT team, having cleared the two-story auditorium, is entering into the school’s music area on the second floor where there are reports of students hiding in a music room closet. The team discovers 60 students and evacuates them in groups of 10 through a protective wall of SWAT officers and out the west side.
    ·      The same SWAT team then moves into an area across the hallway and to the left of the music room where an additional 60 students are found and safely evacuated from the building.
         14:26 --  Sgt. Domenico, surveying the area from Channel 7 news helicopter, reports that someone is trying to climb out a second story window on the southwest side of the school.
         14:28 --  Simmons advises that the administration area on the upper level is cleared and his group is moving to the art and consumer education areas.
         14:29 -- ·        The Jefferson County Sheriff’s Office requests Littleton Fire to dispatch engines and rescue units to Eric Harris’ residence.  Already on scene are the Sheridan and Lakewood Police Department investigators, ATF personnel and Arapahoe County bomb technicians preparing to investigate a gasoline smell and the report of a bomb at the residence.
         14:30 --  Having just searched the business and computer classrooms, the first half of Williams’ team clears the stairs to the upper level.  Once on the upper level, Williams sees Simmons’ team clearing the school to the east of where he stands.
         14:33 -- ·        President Clinton refers to the shooting at a high school in Littleton, Colorado, during a scheduled news conference to talk about the American economy. “Ladies and Gentlemen, we all know there has been a terrible shooting at a high school in Littleton, Colorado.  Because the situation, as I left to come out here, apparently is ongoing, I think it would be inappropriate for me to say anything other than I hope the American people will be praying for the students, the parents and the teachers and we’ll wait for events to unfold and there will be more to say.”
         14:38 --  Patrick Ireland (w24), shot in the library and slipping in and out of consciousness, has slowly made his way to the west window.  Sgt. Domenico, in a news helicopter, and deputies on the south and west sides of the school see a figure at the window and realize the young man is attempting to climb out the second story broken window.  The only thing below him is a concrete sidewalk. The image of Patrick’s rescue has come to epitomize the Columbine tragedy.  Using the roof of an armored vehicle so they can reach him, several Lakewood SWAT members catch the young man as he falls out the window .
         14:39 --  Patrick Ireland is transported to St. Anthony’s Hospital.
    14:40 --  Forty students are evacuated out of the vocal room. --  Littleton Fire shuts off the electricity and natural gas to the Harris’ residence.
         14:42 --  Williams’ SWAT team requests medical assistance to the science area on the second floor, west side, for a teacher with multiple gunshot wounds. The teacher is Dave Sanders. -- ·        Williams’ also announces that 60 students are to be evacuated from this same area.
         14:47 --  Members of Williams’ SWAT team evacuate approximately 60 people from the science area. Two SWAT members move the students and teachers first to the stairway landing, then down to the lower level and through the recently cleared cafeteria and out the west side door.  Two SWAT members stay with Sanders waiting for paramedics.
         14:52 --  Simmons’ SWAT team working on the upper east side of the building announces the band room and woodshop areas are clear.  The team is progressing west down the hallways to clear various rooms including a gym and weight room.
         15:12 – 15:17 --  Fifty students are evacuated from the east upper level and are directed across the street to safety.
    15:22 - 15:37 --  The first team to enter the library is Williams’ team of four Jefferson County SWAT members.  A Denver SWAT officer holds the doorway. The four Jefferson County members spread out and work their way through sections of the library.  They step over numerous bombs trying to get to each one of the children.
    --  Among three victims laying on the floor under desks is Lisa Kreutz (w21) .  She has been shot several times but she is alive. SWAT, seeing her wounds, calls for a paramedic. --  In addition to the one girl who is injured, Williams’ team reports that they have found 12 dead.  Among the 12 are two males on the floor in the southwest part of the library who appear to have self-inflicted gunshot wounds to the head.  Guns and numerous explosive devices lay on the ground beside the bodies. Williams advises the command post that the two males match the description of the suspects.
    --  A female employee, hiding in the magazine room in a back part of the library, comes out of hiding.  She is instructed to put her hand on the back of one of the SWAT officers, look only at the back of his helmet and follow him out of the library.  She is quickly passed off to another officer and evacuated to the outside. 
    --  Three other employees subsequently are evacuated from the library, including teacher Patti Nielson who was hiding in a cupboard in a west room of the library.
    --  Williams’ SWAT team works its way to the back emergency door that opens to the outside upper level near the west entrance.  Although several bombs are laying inside the door, the SWAT team realizes the urgent need to get a team of paramedics into the library to attend to Lisa Kreutz. Two paramedics come in with a backboard, put the wounded student on it and quickly get her out of the library.  Lisa is transported to Denver Health Medical at 15:37.
    --  After searching the library, Williams’ SWAT team requests the bomb squad. 
    --  The other half of Williams’ team and Simmons’ SWAT team, still searching other parts of the school building, hear over the radio that William’s first team has made it to the library and found one female still alive. They continue clearing classrooms on the upper levels, working their way toward the library.
    15:25 --  Littleton Fire reports that live bombs and gasoline have been located at the Harris residence. Adjacent houses in the neighborhood are evacuated.
         15:36 -- SWAT command personnel meet at the east doors of the school to discuss follow up sweeps of the school and to relieve initial teams, replenishing them with fresh SWAT teams from other agencies.
    ·      Simmons’ team, after clearing the gymnasium and weight room, enters a north-south hallway which is where the library is located.  The team arrives outside the library as Williams’ team completes clearing the library.
    15:40 --  Teacher Patti Nielson is transported to Littleton Hospital.
    15:55 --  Lakewood SWAT reports two cars on the southwest side of the school are possibly booby trapped.  One car is described as being a black Honda Civic, Mercedes or BMW with NIN bumper stickers.  The other is a blue 1980’s two-door with a Ramstein sticker.
    16:00 --  Bomb technicians remove an explosive device from the Harris residence.
    16:04 --  A Littleton fire captain enters the school and is able to silence the fire alarms and shut off the emergency sprinkler systems.
         16:35 --  Two explosions are reported on the north side of the school.  SWAT advises that they are shock locks fired by a SWAT team.  Shock locks are explosive devices used to gain entry into locked rooms.
         16:38 --  Dr. Christopher Colwell, attending emergency room physician at Denver Health Medical Center, and Robert Montoya, a Denver Health paramedic, are escorted by SWAT team members through the library “to look for any signs of life.”  Dr. Colwell had already pronounced Rachel Scott and Daniel Rohrbough, two of the youths shot outside, as dead.
         16:45 --  Colwell performs a second sweep of the library, this time pronouncing each of the 10 victims and the two suspects dead.  He is also escorted to the science area where he pronounces teacher Dave Sanders as dead.
    Making the Scene Safe --     By 16:45, the SWAT teams finished the initial search of Columbine High School, clearing the  250,000 square-foot two-story building. The deceased, including two suspects, had been checked and pronounced dead by Dr. Colwell of the Denver Health Medical Center.  The deadly shootings and massacre at Columbine was over.