Editing Columbine High School massacre (section)

==The massacre==
According to the shooters' respective journals and video tapes, it is believed by investigators that the pair intended to detonate their propane bombs in the cafeteria at the busiest lunch hour,<ref>{{Cite AV media |title=Uncovering The Tragedy At Columbine High: A Mass Shooting Documentary |others=Real Crime, producer |url=https://www.youtube.com/watch?v=D9mUpUHk3nE |via=YouTube |date=10 May 2019 |access-date=2023-02-12 |time=27m40s |last=Battan |first=Kate |quote=Eric Harris had even gone so far as to study how many people were in the cafeteria at any given time during the lunch hour. ... Approximately 450 [at peak period] is what he was estimating, and we had 455 kids down there.}}</ref> killing hundreds of students. After this, they would shoot and stab survivors, as well as lob bombs. Bombs set in their cars in the parking lot would also eventually detonate, killing more students as well as possibly any police officers, paramedics, firemen, or reporters who had come to the school.<ref name=ten /><ref>{{cite news |url=http://news.bbc.co.uk/2/hi/americas/329303.stm |title=Columbine killers planned to kill 500 |date=April 27, 1999 |access-date=October 15, 2014 |archive-url=https://web.archive.org/web/20100515095812/http://news.bbc.co.uk/2/hi/americas/329303.stm |archive-date=May 15, 2010 |url-status=live |work=BBC News}}</ref>{{efn|Investigators speculated they were supposed to detonate after the massacre and injure first responders.<ref>''The Columbine School Shootings'' {{ISBN|978-1-420-50138-4}} p. 65</ref>}} However, the bombs in the cafeteria and cars failed to detonate.<ref>{{cite news |last=Cullen |first=Dave |date=April 24, 2009 |title=The Reluctant Kller |newspaper=[[The Guardian]] |url=https://www.theguardian.com/world/2009/apr/25/dave-cullen-columbine |access-date=July 15, 2020 |issn=0261-3077 |ref=none}}</ref>

Several official sources claim they planned to shoot the fleeing survivors from the parking lot, but when the bombs failed, they moved to the staircase on the hill at the west side.<ref>''E.g.'', {{cite web |url=https://schoolshooters.info/sites/default/files/Columbine%20-%20Governor's%20Commission%20Report.pdf |title=Governor's Report |page=26}}</ref> Other sources claim the top of the staircase where the massacre began was their preferred spot to wait for the bombs to go off all along.<ref>{{Harvnb|Krabbé|2012|pp=31, 41}}</ref>{{efn|Klebold made notes prior to the massacre which included "Go to the outside hill, wait. When first bombs go off, attack."<ref name=suspdk/>}}

A total of 188 rounds of ammunition were fired by the perpetrators during the massacre. Firing nearly twice as much as Klebold, Harris fired his carbine rifle a total of 96 times: 47 shots outside, 36 shots inside, and 13 shots in the library. Harris also discharged his shotgun 25 times: 21 times in the library and four times inside. He did not fire his shotgun outside the school. Klebold fired the TEC-9 handgun 55 times: three shots outside, 31 shots inside, and 21 shots in the library. Klebold also fired 12 rounds from his double-barreled shotgun: twice outside, four times inside, and six times in the library. Law enforcement officers fired 141 rounds during exchanges of gunfire with the shooters.<ref name="crit">{{cite news |title=The Critical Incident Team |work=CNN |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/SHOOT_TEAM_TEXT.htm |url-status=live |access-date=April 9, 2017 |archive-url=https://web.archive.org/web/20170315125026/http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/SHOOT_TEAM_TEXT.htm |archive-date=March 15, 2017}}</ref><ref name="cnnrep">{{cite news |date=May 16, 2000 |title=Report: 12 killed at Columbine in first 16 minutes |work=CNN |url=http://www.cnn.com/2000/US/05/15/columbine.report.04/ |url-status=dead |archive-url=https://web.archive.org/web/20000818101434/http://www.cnn.com/2000/US/05/15/columbine.report.04/ |archive-date=August 18, 2000}}</ref>

=== Planting the bombs ===
On Tuesday morning, April 20, 1999, Harris and Klebold placed two duffel bags in the cafeteria. Each bag contained propane bombs, set to detonate during the "A" lunch shift, which began at 11:15&nbsp;a.m.{{efn|All times are in [[Mountain Time Zone|Mountain Daylight Time]], [[UTC-6]].<ref>{{Harvnb|Cullen|2009|p=45}}</ref>}}

No witness recalled seeing the duffel bags being added to the 400 or so backpacks that were already in the cafeteria.<ref name="timeline1">Columbine Report, {{cite news |date=May 15, 2000 |title=The Columbine High School Shootings: Narrative Time Line of Events 11:10 AM to 11:59 AM |work=CNN |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/NARRATIVE.Time.Line.htm |url-status=live |access-date=December 26, 2012 |archive-url=https://web.archive.org/web/20121215192448/http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/NARRATIVE.Time.Line.htm |archive-date=December 15, 2012}}</ref> The security staff at CHS did not observe the bags being placed in the cafeteria; a custodian was replacing the school security videotape at around 11:14&nbsp;a.m.<ref name="duffle">{{Cite web |title=dufflebags |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/dufflebags.htm |access-date=2022-01-12 |website=www.cnn.com}}</ref> Shortly after the massacre, police speculated the bombs were placed during this "tape change". They also investigated whether the bombs were placed during the "after-prom" party held the prior weekend.<ref name="duffle" /><ref>{{cite web |url=http://extras.denverpost.com/news/shot0424a.htm |title=Columbine - Tragedy and Recovery |website=The Denver Post}}</ref><ref>{{cite web |url=http://extras.denverpost.com/news/shot0501d.htm |title=What happened on prom night? |first=Patricia |last=Callahan |author-link=Patricia Callahan |website=The Denver Post}}</ref> Some [[Websleuths|Internet sleuths]] claim the bomb placement can be seen on the surveillance video at around 10:58&nbsp;a.m.<ref>{{cite web |last=Prendergast |first=Alan |date=July 8, 2016 |title=Video: Did Police Investigation Miss Key Moment in Columbine Attack? |url=https://www.westword.com/news/video-did-police-investigation-miss-key-moment-in-columbine-attack-8079357}}</ref> Harris and Klebold are seen in the tapes planting the bombs in casual school clothes separately.

Jefferson County Sheriff's Deputy Neil Gardner was assigned to the high school as a full-time [[school resource officer]]. Gardner usually ate lunch with students in the cafeteria, but on April 20 he was eating lunch in his patrol car at the northwest corner of the campus, watching students in the Smokers' Pit in Clement Park, a meadow adjacent to the school.<ref name=deputies>Columbine Report, {{cite news |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/DEPUTIES_TEXT.htm |title=Deputies on Scene |access-date=December 24, 2012 |archive-url=https://web.archive.org/web/20121222141354/http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/DEPUTIES_TEXT.htm |archive-date=December 22, 2012 |url-status=live}}</ref>

Two backpacks filled with pipe bombs, aerosol canisters, and small propane bombs were also placed in a field about {{convert|3|mi}} south of CHS, and {{cvt|2|miles}} south of the fire station.{{efn|On the corner of South Wadsworth Boulevard and Ken Caryl Avenue.<ref>{{Cite web |title=Diversion_map |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/Diversion_MAP.htm |access-date=2022-01-12 |website=www.cnn.com}}</ref>}} The bombs were intended as a diversion to draw firefighters and emergency personnel away from the school. Only the pipe bombs and one of the aerosol canisters detonated, causing a small fire, which was quickly extinguished by the fire department. It went off after first having been moved. Bomb technicians immediately examined the bombs and relayed to police at the school the possibility of devices with motion activators.<ref name=bombsum />

Harris and Klebold changed clothes and returned separately to CHS. Harris parked his vehicle in the junior student parking lot, and Klebold parked in the adjoining senior student parking lot. The school cafeteria was their primary bomb target; the cafeteria had a long outside window-wall, ground-level doors, and was just north of the senior parking lot.<ref>Columbine Report, Diagram 12</ref> The library was located above the cafeteria in the second-story of the window-wall. Each car contained bombs.<ref name="guidebomb" /><ref>{{Harvnb|Klebold|2016|p=131}}</ref>

As Harris pulled into the parking lot, he encountered classmate Brooks Brown, with whom he had recently patched up a longstanding series of disputes. According to Brown, who was smoking a cigarette, he was surprised to see Harris, whom he earlier noted had been absent from a class test. Harris, a good student, was unlikely to miss school days with important academic obligation.<ref>Columbine Documents. (1999). ''Columbine Documents'' (Report no. JC-001-026323) Jefferson County Sherriff's Office. http://www.acolumbinesite.com/reports/cr/p25923-26859-936columbinedocs.pdf</ref> Brown berated Harris for missing the test. Harris, acting unconcerned, replied "It doesn't matter anymore." Harris went on: "Brooks, I like you now. Get out of here. Go home." Brown, feeling uneasy and already prepared to skip his next class, walked away down South Pierce Street.<ref name=brooks13>{{Harvnb|Brown|2002|pp=13–15}}</ref>

Meanwhile, Harris and Klebold armed themselves, using straps and webbing to conceal weapons beneath their [[trench coat]]s. They lugged bags containing bombs and ammunition. Harris had concealed his shotgun in one of the bags. Beneath the trench coats, Harris wore a military [[bandolier]] and a white T-shirt with the inscription "[[Natural selection|Natural Selection]]" in black letters, a mantra he had adopted; Klebold wore a black T-shirt with "Wrath" in red letters.<ref>{{Harvnb|Cullen|2009|p=41}}</ref>

The cafeteria bombs failed to detonate. Had these explosives detonated as intended, they would have killed or severely wounded the 488 students in the cafeteria and damaged the school's structure, collapsing the library into the cafeteria and possibly killing more students and staff.<ref name="bombsum" />

===11:19&nbsp;a.m.: Shooting begins===
At 11:19&nbsp;a.m., 17-year-old [[Rachel Scott]] and her friend Richard Castaldo were having lunch and sitting on the grass next to the west entrance of the school. Klebold threw a pipe bomb towards the parking lot; the bomb only partially detonated, causing it to give off smoke. Castaldo thought it was no more than a crude senior prank. Likewise, several students during the incident first thought that they were watching a prank.<ref name=eyes/><ref name=librev/>

The two allegedly returned to where Rachel Scott and Richard Castaldo lay on the ground injured.{{clarify|reason=Injured from gunshots most likely, but information seems to be missing here as the previous paragraph does not mention it.|date=March 2025}} Scott was killed instantly when she was hit four times with rounds fired from Harris's [[carbine]]; one shot was to the [[Temple (anatomy)|left temple]].<ref name=OOL>{{Cite book |url=http://www.acolumbinesite.com/reports/cr/p11867-11870.pdf |archive-url=https://web.archive.org/web/20181007023504/http://www.acolumbinesite.com/reports/cr/p11867-11870.pdf |archive-date=October 7, 2018 |page=JC-001-011868 |chapter=Columbine High – OOL Deceased |title=Columbine High School 99-7625 Evidence |volume=2 |access-date=October 6, 2018 |publisher=Jefferson County Sheriff's Office |location=Colorado}}</ref> Castaldo was shot eight times in the chest, arm, and abdomen by both Harris and Klebold; he fell unconscious to the ground and was left [[Paralysis|paralyzed]] below the chest.<ref>{{Harvnb|Cullen|2009|p=46}}</ref>

After firing twice, Klebold's TEC-9 jammed, and he was forced to temporarily cease shooting to fix it, which he did by reloading a new magazine into his pistol. Meanwhile, Harris took off his trenchcoat and aimed his carbine down the west staircase in the direction of three students: Daniel Rohrbough, Sean Graves, and Lance Kirklin. The students presumed they were [[Paintball marker|paintball guns]], and were about to walk up the staircase directly below the shooters. Harris fired ten times, killing Rohrbough<ref>{{cite web |url=http://www.hpwhite.com/wp-content/uploads/2013/12/COLUMBINE_HPW.pdf#page=28 |title=Reinvestigation into the Death of Daniel Rohrbough at Columbine High School on April 20, 1999 |publisher=El Paso County Sheriff's Office |access-date=January 4, 2019 |archive-date=October 27, 2018 |archive-url=https://web.archive.org/web/20181027101335/http://www.hpwhite.com/wp-content/uploads/2013/12/COLUMBINE_HPW.pdf#page=28}}</ref> and injuring Graves and Kirklin.<ref name=timeline1 /> William David Sanders, a teacher and coach at the school, was in the cafeteria when he heard the gunfire and began warning students.<ref name=dave>{{cite web |url=http://www.acolumbinesite.com/victim/sanders.php |title=Coach William "Dave" Sanders |website=acolumbinesite.com}}</ref>

Harris turned west and fired seven shots in the direction of five students sitting on the grassy hillside adjacent to the steps and opposite the west entrance of the school:<ref name=timeline1 /> Michael Johnson was hit in the face, leg, and arm but ran and escaped; Mark Taylor was shot in the chest, arms, and leg and fell to the ground, where he faked death; the other three escaped uninjured.<ref name=timeline1 />

Klebold fired down the stairs with his shotgun, injuring Nicholas "Nick" Foss with a graze wound, then walked down the steps toward the cafeteria. He came up to Lance Kirklin, who was already wounded and lying on the ground, weakly calling for help. Klebold said, "Sure. I'll help you," then shot Kirklin in the jaw with his shotgun. Although near-fatally injured, Kirklin would survive.<ref name=eyes>{{cite news |url=http://extras.denverpost.com/news/shot0613a.htm |title=Through the Eyes of Survivors |access-date=March 16, 2017 |newspaper=The Denver Post |date=June 13, 1999 |archive-url=https://web.archive.org/web/20161114133750/http://extras.denverpost.com/news/shot0613a.htm |archive-date=November 14, 2016 |url-status=live}}</ref><ref>{{cite web |url=http://extras.denverpost.com/news/col0416a.htm |title=Lance Kirklin's story |date=April 16, 2000 |first=Kevin |last=Simpson}}</ref> Graves—paralyzed beneath the waist—had crawled into the doorway of the cafeteria's west entrance and collapsed. He rubbed his blood on his face and played dead.<ref name=surfive>{{cite news |url=https://news.google.com/newspapers?nid=1980&dat=20040418&id=VXMyAAAAIBAJ&pg=1302,2595537 |title=Survivors push forward 5 years after Columbine shootings |access-date=August 24, 2016 |newspaper=The Item |date=April 18, 2004}}</ref><ref name=five/> After shooting Kirklin, Klebold walked towards the cafeteria door. He then stepped over the injured Graves to enter the cafeteria.<ref name=surfive/> Graves remembers Klebold saying, "Sorry, dude."<ref>{{Citation |title=Chaos at Columbine: Revisiting the Tragedy 17 Years Later - Pt. 2 - Crime Watch Daily | date=April 20, 2016 |url=https://www.youtube.com/watch?v=o4zwrbuncL8 |language=en |access-date=2022-01-12}}</ref>

Klebold then only briefly entered the cafeteria and did not shoot at the several people still inside. Officials speculated that Klebold went to check on the [[propane bomb]]s. Harris was still on top of the stairs shooting, and severely wounded and partially paralyzed 17-year-old [[Anne Marie Hochhalter]] as she attempted to flee.<ref name=surfive/><ref name=five/>{{efn|Hochhalter would die of her injuries on February 19, 2025, at the age of 43. Her death certificate lists her cause of death as [[sepsis]] due to [[Streptococcus pyogenes]]. Her death was officially ruled a homicide.<ref name=kdvr>{{Cite web |last=Willard |first=Heather |date=12 March 2025 |title=Coroner report: Columbine survivor's death 'best classified as homicide' |url=https://kdvr.com/news/local/coroner-report-columbine-survivors-death-best-classified-as-homicide/ |url-status=live |archive-url=https://web.archive.org/web/20250313161626/https://kdvr.com/news/local/coroner-report-columbine-survivors-death-best-classified-as-homicide/ |archive-date=13 March 2025 |access-date=14 March 2025 |website=FOX31 KVDR}}</ref> }}

Klebold came out of the cafeteria and went back up the stairs to join Harris.<ref name=timeline1 /> They each shot at students standing close to a soccer field but did not hit anyone. They walked toward the west entrance, throwing pipe bombs in several directions, including onto the roof; only a few of these pipe bombs detonated. Witnesses heard one of them say, "This is what we always wanted to do. This is awesome!"<ref name=event1/>

Meanwhile, art teacher Patti Nielson was inside the school; she had noticed the commotion and walked toward the west entrance with student Brian Anderson. Nielson had intended to walk outside to tell the two students, "Knock it off",<ref name=timeline1 /> thinking they were either filming a video or pulling a student prank.<ref name=eyes/> As Anderson opened the first set of double doors, the gunmen shot out the windows, injuring him with flying glass; Nielson was hit in the shoulder with shrapnel. Anderson and Nielson ran back down the hall into the library, and Nielson alerted the students inside to the danger, telling them to get under desks and keep silent. She dialed [[9-1-1]] and hid under the library's administrative counter.<ref name=timeline1 /> Anderson fell to the floor, bleeding from his injuries, then hid inside the magazine room adjacent to the library.<ref>{{cite book |last1=Cashman |first1=John R. |title=Emergency Response Handbook for Chemical and Biological Agents and Weapons |date=2008 |publisher=CRC Press |location=Boca Raton, Florida |isbn=978-1-4200-5266-4 |page=53}}</ref>

===11:22&nbsp;a.m.: Police response and West Entrance shootouts===
At 11:22&nbsp;a.m., a custodian called Deputy Neil Gardner, the assigned resource officer to Columbine, on the school radio, requesting assistance in the senior parking lot. The only paved route took him around the school to the east and south on Pierce Street, where at 11:23&nbsp;a.m., he heard on his police radio that a female was down, and assumed she had been struck by a car. While exiting his patrol car in the senior lot at 11:24, he heard another call on the school radio, "Neil, there's a shooter in the school."<ref name=deputies />

Harris, at the west entrance, immediately turned and fired ten shots from his carbine at Gardner, who was {{Convert|60|yards|m}} away.<ref name=deputies /> As Harris reloaded his carbine, Gardner leaned over the top of his car and fired four rounds at Harris from his service pistol.<ref name=eyes/><ref>{{Harvnb|Kass|2009|p=8}}</ref> Harris ducked back behind the building, and Gardner momentarily believed that he had hit him. Harris then reemerged and fired at least four more rounds at Gardner (which missed and struck two parked cars), before retreating into the building. No one was hit during the exchange of gunfire.{{efn|Gardner was not wearing his prescription eyeglasses.<ref>{{cite news |first=Trent |last=Seibert |date=November 23, 2000 |title=Columbine: Deputy's eyesight in question |url=http://extras.denverpost.com/news/col1123b.htm |work=The Denver Post |access-date=October 15, 2014 |archive-url=https://web.archive.org/web/20150322205016/http://extras.denverpost.com/news/col1123b.htm |archive-date=March 22, 2015 |url-status=live}}</ref>}} Gardner reported on his police radio, "Shots in the building. I need someone in the south lot with me."<ref name=deputies /> By this point, Harris had shot 47 times, and Klebold 5.<ref name=crit/> The shooters then entered the school through the west entrance, moving along the main north hallway, throwing pipe bombs and shooting at anyone they encountered. Klebold shot Stephanie Munson in the ankle, but she was able to walk out of the school.<ref name=eyes/> The pair then shot out the windows to the east entrance of the school. After proceeding through the hall several times and shooting toward—and missing—any students they saw, they went toward the west entrance and turned into the library hallway.{{sfn|Watson|2003|p=198}}

Deputies Paul Smoker and Paul Magor, motorcycle patrolmen for the Jefferson County Sheriff's Office, were writing a traffic ticket north of the school when the "female down" call came in at 11:23&nbsp;a.m. Taking the shortest route, they drove their motorcycles over grass between the athletic fields and headed toward the west entrance. When they saw Deputies Scott Taborsky, Rick Searle, and Kevin Walker following them in their patrol car, they abandoned their motorcycles for the safety of the car. The six deputies had begun to rescue two wounded students near the ball fields when another gunfight broke out at 11:26, as Harris returned to the double doors and again began shooting at Deputy Gardner, who returned fire. From the hilltop, Deputy Smoker fired three rounds from his pistol at Harris, who again retreated into the building. As before, no one was hit.<ref name="timeline1" /><ref name="deputies" />

Inside the school cafeteria, Dave Sanders and two custodians, Jon Curtis and Jay Gallatine, initially told students to get under the tables, then evacuated students up the staircase leading to the second floor of the school. The stairs were located around the corner from the library hallway in the main south hallway. Sanders then tried to secure as much of the school as he could.<ref name=eyes/><ref name=dave /> Sanders and another student were at the end of the hallway, where he gestured for students in the library to stay, before encountering Harris and Klebold, who were approaching from the corner of the north hallway. Sanders and the student turned and ran in the opposite direction.<ref name=":5">{{cite news |first1=Lou |last1=Kilzer |first2=Gary |last2=Massaro |url=http://www.denver-rmn.com/shooting/0516dave3.shtml |title=Science teacher died a hero |newspaper=Rocky Mountain News |archive-url=https://web.archive.org/web/20070927234555/http://www.denver-rmn.com/shooting/0516dave3.shtml |archive-date=September 27, 2007}}</ref> Harris and Klebold shot at them both, with Harris hitting Sanders twice in the back and neck, hitting his teeth on exit, but missing the student.<ref name=eyes/><ref name=dave /> The latter ran into a science classroom and warned everyone to hide. Klebold walked over towards Sanders, who had collapsed, and tossed a pipe bomb, then returned to Harris up the library hallway.<ref>{{Harvnb|Cullen|2009|p=139}}</ref>

Sanders struggled toward the science area, and teacher Rich Long took him into a classroom where 30 students were located. Due to his knowledge of first aid, student Aaron Hancey was brought to the classroom from another by teacher Kent Friesen despite the unfolding commotion. With the assistance of fellow student Kevin Starkey and teacher Theresa Miller, Hancey administered first aid to Sanders for three hours, attempting to stem the blood loss using shirts from students in the room, and showing him pictures from his wallet to keep him talking.<ref name=eyes/><ref name=hancey>{{cite web |last=Trostle |first=Pat |url=http://news.hjnews.com/columbine-hero-has-local-ties/article_b823be2b-4681-53c7-b595-0d7b1380190d.html |title=Columbine hero has local ties |date=February 2, 2000 |access-date=April 9, 2017 |archive-url=https://web.archive.org/web/20170310234158/http://news.hjnews.com/columbine-hero-has-local-ties/article_b823be2b-4681-53c7-b595-0d7b1380190d.html |archive-date=March 10, 2017 |url-status=live}}</ref><ref>{{Harvnb|Klebold|2016|p=129}}</ref> Using a phone in the room, Miller and several students maintained contact with police outside the school.<ref>{{Harvnb|Cullen|2009|p=141}}</ref>

As the shooting unfolded, pipe bombs were tossed in the hallways and down into the cafeteria. Patti Nielson in the library called 9-1-1, telling her story and urging students in the library to take cover beneath desks. According to transcripts, her call was received by a [[Dispatcher|9–1–1 operator]] at 11:25:18&nbsp;a.m.<ref name="patti">{{cite video |url=http://i.cnn.net/cnn/SPECIALS/2000/columbine.cd/videos/PATTI.mpg |title=PATTI |publisher=Jeffco 911 |access-date=October 15, 2014 |archive-url=https://web.archive.org/web/20110514003812/http://i.cnn.net/cnn/SPECIALS/2000/columbine.cd/videos/PATTI.mpg |archive-date=May 14, 2011 |url-status=live}}</ref>
{{anchor|quotebox}}{{Quote box
| width = 33%
| qalign = left
| qstyle = padding-right:1.5em;
| title = Fatalities
| quote = {{olist
 |'''[[Rachel Scott]]''' (aged 17), killed on grass outside west entrance by Harris
 |'''Daniel Rohrbough''' (aged 15), killed at bottom of stairs leading to west entrance by Harris
 |'''[[Anne Marie Hochhalter]]''' (aged 17), shot and injured outside the school by Harris; died of injuries in February 2025
 |'''William David Sanders''' (aged 47), shot in hallway adjacent library by Harris; died of blood loss in a science classroom
 |'''Kyle Velasquez''' (aged 16), killed while sitting in a chair near the middle of the north computer table in the library by Klebold
 |'''Steven Curnow''' (aged 14), killed at the west end of the south computer table in the library by Harris
 |'''[[Cassie Bernall]]''' (aged 17), killed under library table No.&nbsp;19 by Harris
 |'''Isaiah Shoels''' (aged 18), killed under library table No.&nbsp;16 by Harris
 |'''Matthew Kechter''' (aged 16), killed under library table No.&nbsp;16 by Klebold
 |'''Lauren Townsend''' (aged 18), killed under library table No.&nbsp;2 by Klebold
 |'''John Tomlin''' (aged 16), killed next to library table No.&nbsp;6 by Klebold; after being wounded by Harris
 |'''Kelly Fleming''' (aged 16), killed next to library table No.&nbsp;2 by Harris
 |'''Daniel Mauser''' (aged 15), killed under library table No.&nbsp;9 by Harris
 |'''Corey DePooter''' (aged 17), killed under library table No.&nbsp;14 by Klebold
 |'''[[Eric Harris and Dylan Klebold#Eric Harris|''Eric Harris'']]''' (perpetrator) (aged 18), committed suicide via a self-inflicted gunshot wound
 |'''[[Eric Harris and Dylan Klebold#Dylan Klebold|''Dylan Klebold'']]''' (perpetrator) (aged 17), committed suicide via a self-inflicted gunshot wound}}
}}

===11:29–11:36&nbsp;a.m.: Library massacre===
At 11:29&nbsp;a.m., Harris and Klebold entered the library. Fifty-two students, two teachers and two librarians were inside.<ref name="lark5">{{Harvnb|Larkin|2007|p=5}}</ref>

Harris fired his shotgun twice at a desk. Student Evan Todd had been standing near a pillar when the shooters entered the library and had just taken cover behind a photocopier.<ref name="librev" /><ref name="lark6" /> Todd was hit by wood splinters in the eye and lower back but was not seriously injured.<ref name="inju">{{cite web |url=http://acolumbinesite.com/victim/injured6.php#evan |title=Injured Victims |last=Shepard |first=C |website=acolumbinesite.com |access-date=May 23, 2018 |archive-url=https://web.archive.org/web/20180523100301/http://acolumbinesite.com/victim/injured6.php#evan |archive-date=May 23, 2018 |url-status=live}}</ref> He then hid behind the administrative counter.<ref name="librev" />

The gunmen walked into the library, towards the two rows of computers. Sitting at the north row was disabled student Kyle Velasquez. Klebold fired his shotgun, fatally hitting him in the head and back.<ref name=librev/><ref name=OOL/> They put down their ammunition-filled duffel bags at the south—or lower—row of computers and reloaded their weapons. They then walked between the computer rows, toward the windows facing the outside staircase.

Throughout the massacre in the library, they ordered everybody to get up, said how long they had been waiting for this, and seemed to be enjoying themselves, shouting things like "Woo!" after shooting.<ref name="librev" /> While ordering the [[jock (athlete)|jocks]] to stand up, one of the two said, "Anybody with a white hat or a sports emblem on it is dead."<ref name="librev" /><ref name="lark5" /> Wearing a white baseball cap at Columbine was a tradition among sports team members.<ref name="lark5" /> Nobody stood up, and several students tried to hide their white hats.<ref>{{Harvnb|Cullen|2009|p=179}}</ref>

Windows were shot out in the direction of the recently arrived police.<ref>{{Harvnb|Kass|2009|p=37}}</ref> Officers returned fire, and the gunmen retreated from the windows; no one was injured.<ref name="timeline1" /> Klebold removed his trench coat. He then fired his shotgun at a nearby table, injuring three students: Patrick Ireland, Daniel Steepleton, and Makai Hall.<ref name="librev" />

Harris walked toward the lower row of computer desks with his shotgun and fired a single shot under the first desk while down on one knee. He hit 14-year-old Steven Curnow with a mortal wound to the neck.<ref name="OOL" /> He then moved to the adjacent computer desk, injuring 17-year-old Kacey Ruegsegger with a shot which passed completely through her right shoulder, also grazing her neck and severing a major artery.<ref name="OOL" /><ref name="remem">{{cite news |url=https://www.msn.com/en-us/news/other/remembering-columbine/ar-AA2QskL |title=Remembering Columbine |publisher=MSN |date=July 17, 2014 |access-date=August 20, 2016 |archive-url=https://web.archive.org/web/20160826014926/http://www.msn.com/en-us/news/other/remembering-columbine/ar-AA2QskL |archive-date=August 26, 2016 |url-status=live}}</ref> When she started gasping in pain, Harris said, "Quit your bitching."<ref name="five">{{cite web |url=https://people.com/archive/columbine-five-years-later-vol-61-no-15/ |title=Columbine Five Years Later |work=People |date=April 19, 2004 |access-date=November 16, 2016 |archive-url=https://web.archive.org/web/20161117211130/https://people.com/archive/columbine-five-years-later-vol-61-no-15/ |archive-date=November 17, 2016 |url-status=live}}</ref>

Harris then walked to a table south of the lower computer table, with two students underneath: [[Cassie Bernall]] and Emily Wyant. Harris slapped the surface of the table twice as he knelt, and said "[[Peekaboo|Peek-a-boo]]" before shooting Bernall once in the head with the shotgun, killing her.<ref name=OOL/><ref name=autopsy>{{cite web |url=http://www.autopsyfiles.org/columbine.htm/ |archive-url=https://web.archive.org/web/20150811124613/http://www.autopsyfiles.org/columbine.htm/ |archive-date=August 11, 2015 |title=Columbine Massacre Victims}}</ref> Harris at this point held the gun with one hand, and the weapon hit his face in recoil, injuring his nose.{{efn|Prior to her murder, Bernall had her hands on the sides of her head.<ref name=yes>{{cite web |url=https://www.salon.com/1999/09/30/bernall/ |first=Dave |last=Cullen |title=Who said "Yes"? |date=September 30, 1999}}</ref>}} He told Klebold he had done so, and Klebold responded "Why'd you do that?"<ref>{{Harvnb|Kass|2009|p=38}}</ref>

After fatally shooting Bernall, Harris turned toward the next table, where Bree Pasquale sat next to the table rather than under it. Harris's nose was bleeding; witnesses later reported that he had blood around his mouth. Harris asked Pasquale if she wanted to die, and she responded with a plea for her life. Harris laughed and responded "Everyone's gonna die." When Klebold said "shoot her," Harris responded "No, we're gonna blow up the school anyway."<ref name=lark6>{{Harvnb|Larkin|2007|p=6}}</ref>

Klebold noticed Ireland trying to provide aid to Hall, who had suffered a wound to his knee. As Ireland tried to help Hall, his head rose above the table. Klebold shot him a second time, hitting him twice in the head and once in the foot. Ireland was knocked unconscious but survived.<ref name=eyes/> Klebold then walked toward another table, where he discovered 18-year-old Isaiah Shoels, 16-year-old Matthew Kechter, and 16-year-old Craig Scott (Rachel's younger brother), hiding underneath. Klebold called out to Harris that he found a "[[nigger]]" and tried to pull Shoels out from under the table.<ref name="eyes" /><ref name="suit">{{cite news |url=https://news.google.com/newspapers?nid=1314&dat=19991006&id=L2RWAAAAIBAJ&pg=6615,4899761 |title=Massacre Memorial Sparks Suit |work=The Spokesman Review |date=October 6, 1999 |access-date=September 24, 2016}}</ref><ref>{{Harvnb|Kass|2009|p=39}}</ref>

Harris left Pasquale and joined him. According to witnesses, they taunted Shoels for a few seconds, making derogatory racial comments. The gunmen both fired under the table; Harris shot Shoels once in the chest, killing him, and Klebold shot and killed Kechter. Though Shoels was not shot in the head, Klebold said: "I didn't know black brains could fly that far."<ref name="lark7" /> Meanwhile, Scott was uninjured, lying in the blood of his friends, feigning death. Harris then yelled, "Who's ready to die next?!"<ref name="eyes" />

He turned and threw a "cricket" at the table where Hall, Steepleton, and Ireland were. It landed on Steepleton's thigh; Hall quickly noticed it and tossed it behind them, and it exploded in mid-air. Harris walked toward the bookcases between the west and center section of tables in the library. He jumped on one and shook it, apparently attempting to topple it, then shot at the books which had fallen.<ref name=eyes/><ref name=remem/>

Klebold walked to the east area of the library. Harris walked from the bookcase, past the central area to meet Klebold. The latter shot at a display case next to the door, then turned and shot toward the closest table, hitting and injuring 17-year-old Mark Kintgen in the head and shoulder. He then turned toward the table to his left and fired, injuring 18-year-olds Lisa Kreutz, Lauren Townsend, and Valeen Schnurr with the same shotgun blast. Klebold then moved toward the same table and fired several shots with the TEC-9, killing Townsend.<ref name=remem/>

At this point, the seriously injured Valeen Schnurr began screaming, "Oh, my God! Oh, my God!"<ref name=yes/><ref name=lark7>{{Harvnb|Larkin|2007|p=7}}</ref> In response, Klebold asked Schnurr if she believed in the existence of God; when Schnurr replied she did, Klebold asked "Why?" and commented "God is gay." Klebold reloaded but walked away from the table.<ref name=yes/><ref>{{cite web |url=http://acolumbinesite.com/victim/injured6.php |title=Injured and Survivors of the Columbine High School shooting |website=acolumbinesite.com}}</ref><ref name="Kass 2009 page=40">{{Harvnb|Kass|2009|p=40}}</ref>

Harris approached another table where two girls were hiding. He bent down to look at them and dismissed them as "pathetic".<ref name=librev/><ref name=remem/> Harris then moved to another table where he fired twice, injuring 16-year-olds Nicole Nowlen and John Tomlin. Tomlin moved out from under the table. Klebold shot him repeatedly, killing him.<ref name=OOL/><ref name="Kass 2009 page=40"/>
[[File:Columbine library fbi diagram.jpg|thumb|upright|An FBI diagram of the library, with locations of fatalities]]
Harris then walked back over to the other side of the table where Townsend lay dead. Behind the table, 16-year-old Kelly Fleming had, like Bree Pasquale, sat next to the table rather than beneath it due to a lack of space. Harris shot Fleming with his shotgun, hitting her in the back and killing her.<ref name=OOL/> He shot at the table behind Fleming, hitting Townsend, who was already dead; Kreutz again; and wounding 18-year-old Jeanna Park.<ref name=librev /> The shooters moved to the center of the library, where they reloaded their weapons at a table. Harris then pointed his carbine under a table, but the student he was aiming at moved out of the way. Harris turned his gun back on the student and told him to identify himself. It was John Savage, an acquaintance of Klebold's. He asked Klebold what they were doing, to which he shrugged and answered, "Oh, just killing people."<ref name=lark7/> Savage asked if they were going to kill him. Because of the background noise, Klebold said, "What?" Savage asked again whether they were going to kill him. Klebold said no, and told him to run. Savage fled, escaping through the library's main entrance and through the cafeteria.<ref name=librev />

After Savage left, Harris turned and fired his carbine at the table directly north of where he had been, hitting the ear and hand of 15-year-old Daniel Mauser. Mauser retaliated by either shoving a chair at Harris or grabbing at his leg; Harris fired again and hit Mauser in the center of the face at close range, killing him.<ref name=OOL/> Harris then moved south and fired three shots under another table, critically injuring two 17-year-olds, Jennifer Doyle and [[Austin Eubanks]]. Klebold then shot once, fatally wounding 17-year-old Corey DePooter, at 11:35.<ref name="timeline1" /><ref name="librev" /> There were no further victims. They had killed 10 people in the library and wounded 12.{{refn|There were 56 potential victims in the library; investigators would later find that the shooters had enough ammunition to have killed them all.<ref name=timeline1 />}}

Klebold was quoted as saying they might start knifing people, but they never did. They headed towards the library's main counter. Harris threw a Molotov cocktail toward the southwestern end of the library, but it failed to explode. They converged close to where Todd had moved after having been wounded.<ref name="librev" /> Klebold pulled the chair out from the desk, then he pointed his TEC-9 at Todd, who was wearing a white hat. Klebold asked if he was a jock, and when Todd said no, Klebold responded "Well, that's good. We don't like jocks." Klebold then demanded to see his face; Todd partly lifted his hat so his face would remain obscured. When Klebold asked Todd to give him one reason why he should not kill him, Todd said: "I don't want trouble." Klebold responded back angrily "Trouble? You don't even know what fucking trouble is!" Todd tried to correct himself: "That's not what I meant! I mean, I don't have a problem with you guys. I never will and I never did." Klebold then told Harris he was going to let Todd live, but that Harris could kill him if he wanted.<ref name=inju/>

Harris appeared to pay no attention and stated that he and Klebold should head to the cafeteria. Klebold fired into an open library staff break room, hitting a small television. While Harris was walking away, Klebold said, "One more thing!", then picked up the chair beside the library counter under which Patti Nielson was hiding, and slammed the chair down on top of the computer terminal and library counter.<ref name="librev" /> Klebold joined Harris at the library entrance. The two walked out of the library at 11:36. Cautiously, fearing the shooters' return, 10 injured and 29 uninjured survivors began to evacuate the library through the north emergency exit door, which led to the sidewalk next to the west entrance. Kacey Ruegsegger was evacuated from the library by Craig Scott. Had she not been evacuated at this point, Ruegsegger would likely have bled to death from her injuries.<ref>{{cite news |url=http://trib.com/news/state-and-regional/columbine-survivor-in-rose-parade/article_b0245b7c-acc0-5143-b019-684323905931.html/ |title=Columbine survivor in Rose Parade |access-date=August 20, 2016 |newspaper=Casper Star Tribune |date=December 27, 2004}}</ref> Patrick Ireland, unconscious, and Lisa Kreutz, unable to move, remained in the building.<ref name=librev>{{Cite web |title=LIBRARY_TEXT |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/LIBRARY_TEXT.htm |access-date=2022-01-12 |website=www.cnn.com}}</ref> Patti Nielson crawled into the exterior break room, into which Klebold had earlier fired shots, and hid in a cupboard.<ref>Patti Nielson's Statement, Columbine Report documents, p. JC-001-000071</ref>

=== 12:08&nbsp;p.m.: Suicides ===
After leaving the library, Harris and Klebold entered the science area, where they caused a fire in an empty storage closet. It was extinguished by a teacher who had hidden in an adjacent room.{{sfn|Larkin|2007|p=8}} The gunmen then proceeded toward the south hallway, where they shot into an empty science room. At 11:44&nbsp;a.m., they were captured on the school security cameras as they re-entered the cafeteria. The recording shows Harris crouching against the rail on the staircase and firing toward the propane bombs left in the cafeteria, in an unsuccessful attempt to detonate them.<ref>{{cite news |last1=Sarche |first1=Jon |title=Bomb's failure apparently changed Columbine killers' plans |url=https://azdailysun.com/bombs-failure-apparently-changed-columbine-killers-plans/article_5032828f-8505-5cb7-abdc-2ca4924d13ae.html |access-date=15 October 2020 |work=Arizona Daily Sun |date=24 September 1999 |location=Flagstaff, Arizona}}</ref> As Klebold approached the propane bomb and examined it, Harris took a drink from one of the cups left behind. Klebold lit a Molotov cocktail and threw it at the propane bomb. About a minute later, the gallon of fuel attached to the bomb ignited, causing a fire that was extinguished by the fire sprinklers a few minutes later.<ref>{{cite news |last1=Bai |first1=Matt |title=Columbine High School: Anatomy of a Massacre |url=https://www.newsweek.com/columbine-high-school-anatomy-massacre-166950 |access-date=15 October 2020 |work=Newsweek |date=2 May 1999 |location=New York City}}</ref> They left the cafeteria at 11:46.

After leaving the cafeteria, they returned to the main north and south hallways of the school and fired several shots into walls and ceilings as students and teachers hid in rooms. They walked through the south hallway into the main office before returning to the north hallway. At 11:56, they returned to the cafeteria, and briefly entered the school kitchen.<ref name=timeline1/> They returned up the staircase and into the south hallway at 12:00&nbsp;p.m.<ref>{{cite news |url=http://www.cnn.com/SPECIALS/2000/columbine.cd/Pages/NARRATIVE.Time.Line2.htm |title=NARRATIVE TIME LINE |publisher=CNN}}</ref>

They re-entered the library, which was empty of survivors except for the unconscious Ireland and the injured Kreutz. Once inside, at 12:02&nbsp;p.m., police were shot at again through the library windows and returned fire. Nobody was injured in the exchange.<ref name=timeline1/> By 12:05, all gunfire from the school had ceased. By 12:08&nbsp;p.m., both gunmen had killed themselves. Harris sat down with his back to a bookshelf and fired his shotgun through the roof of his mouth; Klebold went down on his knees and shot himself in the left temple with his TEC-9. An article by ''[[The Rocky Mountain News]]'' stated that Patti Nielson overheard them shout "One! Two! Three!" in unison, just before a loud boom.<ref name=Fatal>{{cite news |last1=Bartels |first1=Lynn |first2=Carla |last2=Crowder |url=http://denver.rockymountainnews.com/shooting/0822fata1.shtml |title=Fatal Friendship |newspaper=The Rocky Mountain News |date=1999 |access-date=September 10, 2017 |archive-url=https://web.archive.org/web/20010221031521/http://denver.rockymountainnews.com/shooting/0822fata1.shtml |archive-date=February 21, 2001}}</ref> Nielson later said that she had never spoken with either of the writers of the article.<ref>[http://acolumbinesite.com/reports/cr/p0001-0100.pdf Progress Report, Case # 99-16215] {{Webarchive |url=https://web.archive.org/web/20150904084603/http://www.acolumbinesite.com/reports/cr/p0001-0100.pdf |date=September 4, 2015 }} pp. 98–99</ref>

In 2002, the ''[[National Enquirer]]'' published two [[Post-mortem photography|post-mortem photos]] of Harris and Klebold in the library. Klebold's gun was underneath his body and so unseen in the photo, leading to speculation that Harris shot Klebold before killing himself. However, some of Klebold's blood was on Harris's legs, suggesting that he had fallen onto Harris after Harris had already killed himself.<ref>{{cite journal |journal=The National Enquirer |title=Columbine Killers |date=June 4, 2002}}</ref> Also, just before shooting himself, Klebold lit a Molotov cocktail on a nearby table, underneath which Patrick Ireland was lying, which caused the tabletop to momentarily catch fire. Underneath the scorched film of material was a piece of Harris's brain matter, suggesting Harris had shot himself by this point.<ref>{{Harvnb|Krabbé|2012|p=30}}</ref>