—May 26, 2000: 13-year-old honor student allegedly killed his teacher, Barry Grunow, on last day of classes in Lake Worth, Fla. Nathaniel Brazill is charged with first-degree murder.
—Feb. 29, 2000: 6-year-old boy shot and killed 6-year-old classmate at Buell Elementary School in Mount Morris Township, Mich. Because of his age, the boy was not charged. A 19-year-old man was sentenced to two to 15 years in prison for allowing the boy access to the gun. The boy's uncle has pleaded guilty to possessing the stolen gun used in the shooting.
—Dec. 6, 1999: 13-year-old student fired at least 15 rounds at Fort Gibson Middle School in Fort Gibson, Okla., wounding four classmates. Seth Trickey was convicted on seven assault charges, but will not remain in jail past age 19.
—Nov. 19, 1999: 13-year-old girl shot in the head in school at Deming, N.M., and died the next day. A 12-year-old boy later pleaded guilty and was sentenced to at least two years in juvenile prison.
— May 20, 1999: 15-year-old boy opened fire at Heritage High School in Conyers, Ga., wounding six students. T.J. Solomon later pleaded guilty but mentally ill and was sentenced to 40 years in prison and 65 years of probation.
—Apr. 20, 1999: Two students at Columbine High School in Littleton, Colo., killed 12 students and a teacher and wounded 23 before killing themselves.
—May 21, 1998: Two teen-agers were killed and more than 20 people hurt when a teen-age boy opened fire at a high school in Springfield, Ore., after killing his parents. Kip Kinkel, 17, was sentenced to nearly 112 years in prison.
—May 19, 1998: Three days before his graduation, Jacob Davis, an 18-year-old honor student, opened fire at a high school in Fayetteville, Tenn., killing a classmate who was dating his ex-girlfriend. Davis was sentenced to life in prison.
—April 24, 1998: Andrew Wurst, 15, opened fire at an eighth-grade dance in Edinboro, Pa., killing a science teacher. The boy pleaded guilty to third-degree murder and other charges and is serving 30 to 60 years in prison.
—March 24, 1998: Two boys, 11 and 13, fired on their Jonesboro, Ark., middle school from nearby woods, killing four girls and a teacher and wounding 10 others. Both boys were later convicted of murder and can be held until age 21.
—Dec. 1, 1997: Three students were killed and five wounded at Heath High School in West Paducah, Ky. Michael Carneal, who was 14 at the time of the shooting, pleaded guilty but mentally ill to murder and is serving life in prison.
—Oct. 1, 1997: 16-year-old Luke Woodham of Pearl, Miss., shot two students to death and wounded seven others after killing his mother. He was sentenced to three life sentences plus 140 years.
— Feb. 19, 1997: A 16-year-old boy took a shotgun and a bag of shells to school in Bethel, Alaska, and killed the principal and a student and injured two others. Evan Ramsey is serving a 210-year sentence.