A gunman at a Connecticut elementary school killed 26 people, 20 of them children, and himself on Friday. A look at some other school shootings in years past:

— April 2, 2012: A gunman killed seven people in a rampage at a California Christian university. Jongjin Kim, the Oikos University, said the suspect, One Goh, was angry because administrators refused to grant him a full tuition refund after he dropped out of the nursing program.

— Feb. 27, 2012: Three students were killed and two wounded in a shooting spree that started in a school cafeteria in Chardon, Ohio, as students waited for buses to other schools. Police have charged T.J. Lane, who was 17 at the time, as an adult.

— Feb. 14, 2008: Former student Steven Kazmierczak, 27, opened fire in a lecture hall at Northern Illinois University in DeKalb, Ill., fatally shooting five students and wounding 18 others before committing suicide.

— April 16, 2007: Seung-Hui Cho, 23, fatally shot 32 people in a dorm and a classroom at Virginia Tech in Blacksburg, then killed himself.

— Oct. 2, 2006: Charles Carl Roberts IV, 32, shot to death five girls at West Nickel Mines Amish School in Pennsylvania, then killed himself.

— March 21, 2005: Jeffrey Weise, 16, shot and killed five schoolmates, a teacher and an unarmed guard at a high school on the Red Lake Indian Reservation in Minnesota before taking his own life. Weise had earlier killed his grandfather and his grandfather's companion.

— Oct. 28, 2002: Robert Flores Jr., 41, who was flunking out of the University of Arizona nursing school, shot and killed three of his professors before killing himself.

— March 5, 2001: Charles "Andy" Williams, 15, killed two fellow students and wounded 13 others at Santana High School in Santee, Calif. Continued...