Fatal shootings at US colleges or universities in recent years:
April 16, 2007: A gunman fatally shoots 32 people in a dorm and a classroom at Virginia Tech in Blacksburg, Virginia. The gunman kills himself.
September 2, 2006: Douglas W Pennington, 49, kills himself and his two sons, Logan P Pennington, 26, and Benjamin M Pennington, 24, during a visit to the campus of Shepherd University in Shepherdstown, West Virginia.
October 28, 2002: Failing University of Arizona Nursing College student and Gulf War veteran Robert Flores, 40, walks into an instructor's office and fatally shoots her. A few minutes later, armed with five guns, he enters one of his nursing classrooms and kills two more of his instructors before fatally shooting himself.
January 16, 2002: Graduate student Peter Odighizuwa, 42, recently dismissed from Virginia's Appalachian School of Law, returns to campus and kills the dean, a professor and a student before being tackled by students. The attack also wounds three female students.
August 28, 2000: James Easton Kelly, 36, a University of Arkansas graduate student recently dropped from a doctoral program after a decade of study and John Locke, 67, the English professor overseeing his coursework, are shot to death in an apparent murder-suicide.
August 15, 1996: Frederick Martin Davidson, 36, a graduate engineering student at San Diego State, is defending his thesis before a faculty committee when he pulls out a handgun and kills three professors.
November 1, 1991: Gang Lu, 28, a graduate student in physics from China, reportedly upset because he was passed over for an academic honour, opens fire in two buildings on the University of Iowa campus. Five University of Iowa employees are killed, including four members of the physics department, two other people are wounded. The student fatally shoots himself.
July 12, 1976: Edward Charles Allaway, a custodian in the library of California State University, Fullerton, fatally shoots seven fellow employees and wounds two others. Mentally ill, Allaway believed his colleagues were pornographers and were forcing his estranged wife to appear in their movies. A judge found him innocent by reason of insanity in 1977 after a jury was unable to reach a verdict and he was committed to the state mental health system.
May 4, 1970: Four students were killed and nine wounded by National Guard troops called in to quell anti-war protests on the campus of Kent State University in Ohio.
August 1, 1966: Charles Whitman points a rifle from the observation deck of the University of Texas at Austin's Tower and begins shooting in a homicidal rampage that goes on for 96 minutes. Sixteen people are killed, 31 wounded.