A list of fatal shootings at U.S. colleges or universities in recent years: Aug. 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. May 4, 1970: Four students are killed and nine wounded by National Guard troops called in to quell anti-war protests on the campus of Kent State University in Ohio. July 12, 1976: Edward Charles Allaway, a 37-year-old janitor at California State University, Fullerton, walked into the library with a .22-caliber rifle and killed seven people, wounding two others. Found innocent by reason of insanity, he has been held in a mental institution ever since. Nov. 1, 1991: Gang Lu, 28, a graduate student in physics from China, reportedly upset because he was passed over for an academic honor, opens fire in two buildings on the University of Iowa campus. Five University employees are killed, including four members of the physics department, one other person was wounded. The student fatally shoots himself. Aug. 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. Sept. 17, 1996: 19-year-old Jillian Robbins killed one student and wounded four others with a sniper rifle on the HUB-Robeson Center lawn at Penn State, before being subdued. Claiming to have been suicidal, Robbins plead guilty to third-degree murder and four counts of attempted murder in 1998, and was sentenced to 30-to-60 years in prison. Aug. 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. Jan. 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. Oct. 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. May 9, 2003: Clad in camouflage, Biswanath Halder, 62, a business school alumnus of Case Western Reserve University in Cleveland, Ohio, killed one student and injured two other people during a seven-hour standoff. Almost a hundred people were trapped inside as Halder wandered the halls, firing hundreds of rounds of ammunition, searching for an employee he had sued. He was convicted and sentenced to life in prison. Sept. 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. His sons were seniors at the university. April 2, 2007: A man and a woman were shot to death in the University of Washington's architecture building in an apparent murder-suicide. The female victim, a 25-year-old university employee, had a restraining order against the man, who "almost certainly" shot her and took his own life, according to university police. April 16, 2007: A gunman kills 32 people in a dorm and a classroom at Virginia Tech in Blacksburg, Virginia. The gunman himself later dies.
© 2007 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.