On January 17, 1989 Patrick Edward Purdy, 24, opened fire with a semiautomatic rifle on a Stockton, Calif. schoolyard, killing five children and wounding 29 other students and one teacher before turning the gun on himself.
National Guard troops on the campus of Kent State University in Ohio shot and killed four unarmed students who were protesting the U.S. Invasion of Cambodia on May 4, 1970.
Two young boys, Andrew Golden, 8, and Mitchell Johnson, 10, took seven guns to their Jonesboro, Ark. school on March 24, 1998 and after pulling the fire alarms to evacuate the school, killed four students and one teacher, with nine others wounded. Seven years later they were released from a juvenile detention center.
Just two months later, on May 21, 1998, 15-year-old Kipland Kinkel shot and killed his parents after he was suspended from school for bringing a gun onto campus, and the next day returned to his Springfield, Ore. school where he injured 22 and killed two students. Kinkel is in prison serving 111 years without possibility of parole.
Dylan Klebold, 17, and Eric Harris, 18, killed 12 students on April 20, 1999 when they walked into Columbine High School in Colorado dressed in trench coats with homemade bombs and guns. They then killed themselves.
A 17-year-old named Jeffrey Weise killed nine people, his grandfather and left five others wounded during a mass shooting at Red Lake High School in Minnesota on March 21, 2005, and then also took his own life.
An Amish schoolhouse in Nickel Pines, Penn. turned into the scene of a horrific shooting on October 2, 2006 when Charles Carl Roberts IV, 32, injured five girls critically and shot and killed five others execution-style before killing himself.
In what is the all-time deadliest school shooting in U.S. history, Virginia Tech University student Seung-Hui Cho, 23, shot up the campus on two separate attacks just hours apart on April 16, 2007, killing 32 people before turning the gun on himself. Cho had been diagnosed with a mental illness and the school was found responsible for not alerting campus residents and staff after his first shooting rampage.
On February 27, 2012, 17-year-old T.J. Lane fired 10 shots at a group of students [http://www.radaronline.com/exclusives/2012/02/ohio-shooting-tj-lane-who-photos] in the cafeteria at a high school in Chardon, Ohio. Three students were killed and Lane was arrested.
One L. Goh, 43, killed seven people at Oikos University in California near the Oakland International Airport and was arrested just an hour later.
A 16-year-old female named Brenda Ann Spencer shot a rifle at a San Diego elementary school on January 29, 1979 from her home across the street, killing a janitor, the principal and injuring eight students. Spencer said afterwards she shot at the school because, "I don't like Mondays." She was found guilty and sentenced to 25 years to life in prison.
Responders gather at the scene of a mass school shooting at Sandy Hook Elementary School on December 14, 2012 in Newtown, Connecticut. President Barack Obama wipes tears as he makes a statement in response to the shooting.
Deadliest School Shootings In U.S. History.