Remembering Columbine: 12 Years Later Apr 20, 2011 One of the deadliest school shootings in US history happened 12 years ago. When 2 seniors, Dylan Klebold and Eric Harris, killed 12 students and one teacher. The duo also injured 21 other students at Columbine High School in Littleton, CO. Fox News Radio’s Pam Pusso has the story: