"Early on April 20, I was getting dressed for work when I heard Dylan bound down the stairs and open the front door," writes Susan Klebold, whose son, Dylan, joined Eric Harris in the shooting spree at Columbine High School 10 years ago, killing 12 students and a teacher. "Wondering why he was in such a hurry when he could have slept another 20 minutes, I poked my head out of the bedroom. 'Dyl?' All he said was 'Bye.' The front door slammed, and his car sped down the driveway. His voice had sounded sharp. I figured he was mad because he'd had to get up early to give someone a lift to class. I had no idea that I had just heard his voice for the last time." Susan Klebold writes in next month's O, The Oprah Magazine (via The Denver Post), that she had "no inkling" her son was troubled and suicidal until she read his journals following the incident, in which her son and Harris were also killed. Susan Klebold has declined repeated requests for an interview, according to a statement from Oprah Winfrey, but agreed to write the essay for no compensation. A spokeswoman for the Klebold family says no further statements will be made.

Early this year, Columbine survivors spoke with 5280 about the 10th anniversary of the tragedy. Their stories follow.