Revisiting the Columbine High School Massacre

Police officers led students out of the building, while others stood guard with their weapons pointed at the high school. SWAT teams entered the school about 45 minutes after the shooting began and nearly five hours later, law enforcement declared the school under control. (AP PHOTO/ROCKY MOUNTAIN NEWS/RODOLFO GONZALEZ)

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An aerial view shows students and police officers crouched behind a car outside Columbine High School in Littleton Co. The body of an unidentified person appears at upper center on sidewalk. (RODOLFO GONZALEZ/AP)

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People ran to safety after they were rescued from the building where Harris and Klebold went on a deadly shooting rampage. (REUTERS/GARY CASKEY/FILE PHOTO)

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In this image taken from video, a group of freed students and faculty run from Columbine High School in Littleton, Colo. after two students swept through their school with guns and explosives. (HAL STOELZLE/AP)

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Dressed in military fatigues and carrying high-powered weapons, members of a SWAT team lead an unidentified man is out of Columbine High School. (DAVID ZALUBOWSKI/AP)

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Emergency personnel wheel a wounded male student at a triage site. (GEORGE KOCHANIEC/AP)

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Emergency medical personnel work on a wounded student outside of Columbine High School. (CYRUS MCCRIMMON/AP)

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More than 20 people were wounded in the massacre. (AP PHOTO/THE DENVER ROCKY MOUNTAIN NEWS/GEORGE KOCHANIEC)

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The massacre began a little after 11 a.m. when Eric Harris and Dylan Klebold began shooting fellow students outside of the Columbine, Colorado high school. The two then moved into the school’s library, where many of the victims were killed. (AP PHOTO/KEVIN HIGLEY)

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Emergency responders transported an injured victim to the hospital from the horrific scene at Columbine High School on April 20, 1999. (AP PHOTO/DENVER ROCKY MOUNTAIN NEWS/GEORGE KOCHANIEC)

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Members of a police SWAT march to Columbine High School in Littleton, Colo., as they prepare to do a final search of the school. (ED ANDRIESKI/AP)

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This aerial view shows a triage area near Columbine High School in Littleton, Colo. (RODOLFO GONZALEZ/AP)

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A woman embraces her daughter after they were reunited following a shooting. (ED ANDRIESKI/AP)

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A student is overcome with emotion as he sits down next to a police officer near the triage scene. (GEORGE KOCHANIEC/AP)

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(AP PHOTO/DENVER ROCKY MOUNTAIN NEWS/GEORGE KOCHANIEC)

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Students listened to a classmate’s experience regarding the shooting during a prayer service on April 21, 1999. (AP PHOTO/ CRAIG F. WALKER/POOL)

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Teenagers mourned the loss of a fellow classmate outside of a parking lot near the Columbine High School on April 21, 1999. (AP PHOTO/ROCKY MOUNTAIN NEWS/RODOLFO GONZALEZ)

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Members of the community embrace each other a day after the deadly shootings, as they attend a meeting held for families, teachers, students and friends who were affected by the Columbine High School massacre. (AP PHOTO/ROCKY MOUNTAIN NEWS/LINDA MCCONNELL)

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During the funeral of 16-year-old Matthew Kechter, mourners stood united with their hands held high at St. Frances Cabrini Catholic Church on April 27, 1999. (AP PHOTO/DENVER ROCKY MOUNTAIN NEWS/KEN PAPALEO)