By that time , Klebold had already arrived at the school in a separate car , and the two boys left two gym bags , each containing a 20-pound propane bomb , inside the cafeteria . When these devices failed to detonate , Harris and Klebold launched a shooting attack against their classmates . It was the deadliest attack ever perpetrated at an American high school until the Stoneman Douglas High School shooting on February 14 , 2018 . Harris was responsible for eight of the thirteen confirmed deaths ( Rachel Scott , Daniel Rohrbough , teacher Dave Sanders , Steve Curnow , Cassie Bernall , Isaiah Shoels , Kelly Fleming , and Daniel Mauser ) , while Klebold was responsible for the remaining five ( Kyle Velasquez , Matthew Kechter , Lauren Townsend , John Tomlin , and Corey DePooter ) . There were 24 injured ( 21 of them by the shooters ) , most in critical condition
Stoneman Douglas High School shooting
Stoneman Douglas High School shooting
Eric Harris and Dylan Klebold