Eric David Harris and Dylan Bennet Klebold were American high school seniors who perpetrated the Columbine High School massacre at Columbine High School on April 20, 1999 in Columbine, Colorado. Harris and Klebold killed 12 students, one teacher, and wounded 24 others. After killing most of their victims in the school's library, they died by self-inflicted gunshot wounds. At the time, it was the deadliest high school shooting in U.S. history.