A suspect opened fire at the Abundant Life Christian School in Madison, Wis., on Monday, killing two people and injuring six more before dying of what police believe to be a self-inflicted gunshot wound.
It's one of more than 320 shootings that have taken place on school grounds this year alone, according to the K-12 School Shooting Database.
While school shootings are widespread in the U.S., this one is unusual because of the identity of the suspected perpetrator: Authorities have identified her as a 15-year-old girl.