(New York) There have been 31 school shootings in the United States, since two students turned their weapons on classmates and a teacher in the 1999 Colorado high school massacre that forced communities across America to address youth gun violence and school security. Mary Murphy takes a look at what happened then–and since then in our video.
Below, a list of some violent incidents at U.S. schools over the last 20 years, as complied by CNN:
February 27, 2012 — Chardon High School , Chardon, Ohio. Student Daniel Parmertor, 16, is killed and four others wounded when student T.J. Lane opens fire in the school, authorities say. On February 28, Demetrius Hewlin, 16, dies from his wounds, and Russell King Jr., 17, is declared brain-dead. On March1, T.J. Lane is charged with three counts of aggravated murder, two of attempted aggravated murder and one of felonious assault.
October 2, 2006 — West Nickel Mines School, Nickel Mines, Pennsylvania. Charles Roberts IV, 32, goes to the small Amish school and takes at least 11 girls hostage. Five girls were killed and six others wounded. Roberts then killed himself.
November 8, 2005 — Campbell County Comprehensive High School, Jacksboro, Tennessee. A 15-year-old student opens fire on a principal and two assistant principals, killing one of them and critically wounding another, authorities said.
March 21, 2005 — Red Lake High School, Red Lake, Minnesota. Jeff Weise, 16, kills his grandfather and another adult, four fellow students, a teacher and a security officer. He then killed himself.
March 5, 2001 — Santana High School, Santee, California. Charles “Andy” Williams, 15, kills two classmates, a 14-year old and a 17-year old, and injures 13. Williams is sentenced in 2002 to at least 50 years in prison.
April 20, 1999 — Columbine High School, Littleton, Colorado. Eric Harris, 18, and Dylan Klebold, 17, kill 12 fellow students and one teacher before committing suicide in the school library.
May 21, 1998 — Thurston High School, Springfield, Oregon. After killing his parents the previous day, 15-year old Kip Kinkel returns to Thurston High armed with a rifle. He kills two students in the school cafeteria, a 16- and a 17-year old. He is sentenced to 112 years in prison.
March 24, 1998 — Westside Middle School, Jonesboro, Arkansas. Andrew Golden, 11, and Mitchell Johnson, 13, ambush fellow students and their teachers, killing five. Johnson is incarcerated in a youth facility and released on his 21st birthday in August 2005. Golden is released on his 21st birthday in May 2007.
December 1, 1997 — Heath High School, West Paducah, Kentucky. Michael Carneal, 14, opens fire on a school prayer group, killing three girls. He is serving life in prison.
February 2, 1996 — Frontier Junior High School, Moses Lake, Washington. Barry Loukaitis, 14, takes a rifle to school and kills two classmates and a teacher. He was sentenced to life in prison.
May 1, 1992 — Lindhurst High School, Olivehurst, California. Eric Houston, a 20-year old dropout, returns to his old high school and kills a former teacher and three students. Houston is sentenced to death.
February 26, 1992 — Thomas Jefferson High School, Brooklyn, New York. A 15-year old shoots and kills two other students. The shooter, Kahlil Sumpter, was sentenced in 1993 to between 6 2/3 and 20 years in prison. He was released in 1998.